The Grand Prismatic Spring in Yellowstone National Park is the largest hot spring in the United States, and the third largest in the world, after Frying Pan Lake in New Zealand and Boiling Lake in Dominica. It is located in the Midway Geyser Basin. Grand Prismatic Spring was noted by geologists working in the Hayden Geological Survey of 1871, and named by them for its striking coloration. Its colors include blue, green, yellow, orange, red and brown, and recall the rainbow disperson of white light by an optical prism. The vivid colors in the spring are the result of pigmented bacteria in the microbial mats that grow around the edges of the mineral-rich water. The bacteria produce colors ranging from green to red; the amount of color in the microbial mats depends on the ratio of chlorophyll to carotenoids and on the temperature of the water which favors one bacterium over another. In the summer, the mats tend to be orange and red, whereas in the winter the mats are usually dark green. The center of the pool is sterile due to extreme heat. The deep blue color of the water in the center of the pool results from the intrinsic blue color of water, itself the result of water's selective absorption of red wavelengths of visible light. Though this effect is responsible for making all large bodies of water blue, it is particularly intense in Grand Prismatic Spring because of the high purity and depth of the water in the middle of the spring. The spring is approximately 250 by 300 feet (80 by 90 m) in size and is 160 feet (50 m) deep. The spring discharges an estimated 560 US gallons (2,100 L) of 160 °F (70 °C) water per minute.

At the precipice of Victoria Falls on the border of the African nations of Zimbabwe and Zambia is found perhaps the most unique swimming hole in on the planet. Carved from rock over centuries by the mighty Zambezi River at water’s edge on Livingstone Island, the improbable lagoon dangles 103 meters above the foaming caldron of river water below. The dichotomy of the calm water in the pool and the rapids rushing to the edge of the iconic Victoria Falls, within arms reach, before tumbling over the edge creates a surreal experience considering the thundering roar of the water and the constant rainbows resulting from the ever present spray. The best time to visit the Devil’s Pool is between September and December, the dry season in this part of the world. Livingstone Island is accessible from a nearby hotel where those wishing to swim in the Devil’s Pool must board a small boat that provides transportation to the island where a short hike over the rocky surface to be followed by a short swim in the river puts one in proximity to the pool. This excursion is recommended for those with an adventurous spirit and possessive of good swimming skills. There is a somewhat tamer alternative nearby known as the Angel's Armchair. It’s a natural rock pool as well, somewhat easier to access and recommended for visits from May to October. Victoria Falls is also a destination of choice for other extreme sports pursuits, such as bungee jumping, gorge-swinging and white-water rafting. Your dream trip to Southern Africa would not be complete without including a visit to the famous Victoria Falls. Consider adding a swim in the Devil’s Pool to your list to satisfy that urge to experience all that life has to offer.

Pamukkale, meaning "cotton castle" in Turkish, is a natural site in Denizli Province in southwestern Turkey. The city contains hot springs and travertines, terraces of carbonate minerals left by the flowing water. It is located in Turkey's Inner Aegean region, in the River Menderes valley, which has a temperate climate for most of the year. The ancient city of Hierapolis was built on top of the white "castle" which is in total about 2,700 metres (8,860 ft) long, 600 m (1,970 ft) wide and 160 m (525 ft) high. It can be seen from the hills on the opposite side of the valley in the town of Denizli, 20 km away. Tourism is and has been a major industry. People have bathed in its pools for thousands of years. As recently as the mid-20th century, hotels were built over the ruins of Heropolis, causing considerable damage. An approach road was built from the valley over the terraces, and motor bikes were allowed to go up and down the slopes. When the area was declared a World Heritage Site, the hotels were demolished and the road removed and replaced with artificial pools. Wearing shoes in the water is prohibited to protect the deposits.

Jellyfish Lake is a marine lake located on Eil Malk island in Palau. Eil Malk is part of the Rock Islands, a group of small, rocky, mostly uninhabited islands in Palau's Southern Lagoon, between Koror and Peleliu. There are about 70 other marine lakes located throughout the Rock Islands. Jellyfish Lake is one of Palau's most famous dive (snorkeling only) sites. It is notable for the millions of golden jellyfish which migrate horizontally across the lake daily. Jellyfish Lake is connected to the ocean through fissures and tunnels in the limestone of ancient Miocene reef. However the lake is sufficiently isolated and the conditions are different enough that the diversity of species in the lake is greatly reduced from the nearby lagoon. The golden jellyfish, Mastigiascf, papua etpisoni, and possibly other species in the lake have evolved to be substantially different from their close relatives living in the nearby lagoons. Snorkeling in Jellyfish Lake is a popular activity for tourists to Palau. Several tour operators in Koror offer trips to the lake. Eil Malk island is approximately a 45 minute boat ride from Koror. The lake is accessed by a short trail from the beach on Eil Malk to the lake. Tourists require a pass to access to Jellyfish Lake. The Rock Islands/Jellyfish Lake pass is $35 and is good for 10 days. Scuba diving by tourists in the lake is not allowed. Two reasons are put forward for this: The bubbles from scuba tanks can harm the jellyfish if they collect beneath their bell. The anoxic layer that begins at about 15 meters contains high concentrations of hydrogen sulfide which can be absorbed through the skin of a diver which can lead to death. Jellyfish Lake is currently the only one of Palau's marine lakes open to tourists. Although both species of jellyfish living in the lake have stinging cells (nematocytes), they are not in general powerful enough to cause harm to humans. It has been reported that it is possible to notice the stings on sensitive areas like the area around the mouth. The Fish 'n Fins tour guide recommended that people with allergies to jellyfish consider wearing protective clothing. Saltwater crocodiles are native to Palau but there has only been one death attributed to them in recent times and they are generally not considered a threat to divers. The hydrogen sulfide in the anoxic layer is a serious risk to scuba divers entering this layer. The gas can be absorbed through the skin. In 1977, the maximum safe threshold level for hydrogen sulfide was set at 10 ppm. The concentrations exceed that by eightfold at the bottom of the anoxic layer. However, the hydrogen sulfide concentration down to the chemocline at about 15 metres (49 ft) is reported to be zero, and if the anoxic layer is avoided, the hydrogen sulfide in the lake does not pose a risk for snorkelers. Two species of scyphozoan jellyfish live in Jellyfish Lake, moon jellyfish (Aurelia sp.) and the golden jellyfish (Mastigias sp.). The golden jellyfish are most closely related to the spotted jellyfish (Mastigias papua) that inhabit the nearby lagoons. They are similar to the spotted jellyfish in that they derive part of their nutrition from symbiotic algae (Zooxanthellae) that live in their tissues and part of their nutrition from captured zooplankton. However, the golden jellyfish are morphologically, physiologically, and behaviourally distinct from the spotted jellyfish. They are easily distinguished from the spotted jellyfish by the almost complete loss of spots on the exumbrella and the almost complete loss of their clubs, an appendage attached to the oral arms. Marine biologist Michael Dawson proposed that the golden jellyfish that inhabit Jellyfish Lake be classified as a subspecies (Mastigias cf. papua etpisoni) of the spotted jellyfish living in the nearby lagoons. The species identification is uncertain (denoted by cf. in the name) because the Mastigias papua local to Palauan lagoons may be only one of several cryptic species that make up the M. papua group, and in the future, the M. papua local to Palau may be identified as a separate species from other M. papua. He also proposed that the jellyfish living in four other Palauan marine lakes were distinctive enough to deserve recognition as unique subspecies. The moon jellyfish were identified as Aurelia aurita by Hamner. However, since the release of that report in 1981, genetic testing has been done on specimens of Aurelia collected from locations throughout the world. The results of that testing indicate in addition to the three named species of Aurelia there are at least six other cryptic species in the Aurelia genus. Three of the cryptic species identified were from Palau. One of these cryptic species is common to four of Palau's marine lakes with jellyfish populations including Jellyfish Lake. Hence, the most accurate designation for the moon jellyfish in Jellyfish Lake (as of February 2001) is Aurelia sp. Despite the close proximity of Palau's moon jellyfish cryptic species, Dawson and Jacobs stated that the molecular data suggested that they had not interbred for millions of years.

Caño Cristalesis a Colombian river located in the Serrania de la Macarena, province of Meta. The river is commonly called "The River of Five Colors," "The Liquid Rainbow" or even "The Most Beautiful River in the World" due to the algae produced colors like red, yellow, green and blue at the bottom of the river giving it a unique appearance. A unique biological wonder, Caño Cristales has also been referred as the "river of seven colors," "the river that ran away from paradise," and "the world's most beautiful river." For most of the year, Caño Cristales is indistinguishable from any other river: a bed of rocks covered in dull green mosses are visible below a cool, clear current. However, for a brief period of time every year, the river blossoms in a vibrant explosion of colors. During the short span between the wet and dry seasons, when the water level is just right, a unique species of plant that lines the river floor called Macarenia clavigera turns a brilliant red. It is offset by splotches of yellow and green sand, blue water, and a thousand shades in between. This only happens for a brief period in between seasons. During Colombia's wet season, the water flows too fast and deep, obscuring the bottom of the river and denying the Macarenia clavigera the sun that it needs to turn red. During the dry season there is not enough water to support the dazzling array of life in the river. But for a few weeks from September through November, the river transforms into a veritable living rainbow. Caño Cristales is located in a remote, isolated area not easily accessible by road. Adventurous tourists can now fly into the nearby town of La Macarena. From there it is a short trip into "Serrania de la Macarena," the national park in which Caño Cristales is located. The journey of Macarena to Caño Cristales is done in 3 steps, first a thirty minute boat ride from the Guayabero River, then thirty minutes over land in a 4x4 vehicle and finally thirty minutes on foot. The site was effectively closed to tourists for several years because of guerrilla activity in the region along with concerns about the impact of unregulated tourist traffic. It was reopened to visitors in 2009, and today there are several Colombian Tourist Agencies that will fly travelers to La Macarena. From there, they must make their way to the river site on horseback (or donkeyback) and by foot as part of a guided tour. Visitors are not permitted to stay overnight or cook.

The Blue Lake in Mount Gambier, South Australia that during December to March, the lake turns to a vibrant cobalt blue color, returning to a colder steel grey colour for April to November. The exact cause of this phenomenon is still a matter of conjecture, but it is generally considered likely that it revolves around the warming of the surface layers of the lake during the summer months to around 20 degrees Celsius (70 °F), causing calcium carbonate to precipitateout of solution and enabling micro-crystallites of calcium carbonate to form. This results in scatter of the blue wavelengths of sunlight. During winter the lake becomes well mixed, and recent research indicates that during this phase of the colour cycle the lake is somewhat murkier due to the redistribution of tannins and calcium carbonate particles throughout the lake. Solar elevation has also been found to influence the perceived colour of the lake. The movement of planktonic life-forms within the lake during the seasons and during the day may additionally play a part in the colour change. The lake is one of four crater lakes on Mount Gambier. Of the four lakes, only two remain, as the other two (Leg of Mutton and Brown) have dried up over the past 30 to 40 years as the water table has dropped. Conflicting dates have been estimated for its last eruption, of 28,000 years ago, 4300 years ago., and, most recently, a little before 6000 years ago. If the youngest date is correct, this could be the most recent volcanic eruption on the Australian mainland. Blue Lake is thought to be of an average depth of 72 metres, but in places reaches 75 metres deep (250 feet). The crater rim measures 1,200 metres (3,937 feet) by 824 metres (2,703 feet), however, the lake itself measures 1,087 metres (3,566 feet) by 657 metres (2,155 feet). The bottom of the lake is 30 metres (100 feet) below the level of the main street of the nearby town. The Blue Lake supplies the town with drinking water, providing approximately 3,500 megalitres (2,800 acre·ft) per year from its 36,000 ML (29,000 acre·ft) store. Twelve kilometres (7 mi) south west of Mount Gambier, accessed by taking the turnoff by the Bellum pub, is the Little Blue Lake. It is one of a number of small nearby lakes whose waters also used to turn blue annually. However, pollution from agricultural fertilizers has increased the nutrient levels of these lakes to the extent that they now remain a year-round green colour. Swimming is discouraged and signs for the presence of blue-green algae have been erected. In July 1865 Adam Lindsay Gordon performed the daring riding feat known as Gordon’s Leap on the edge of the Blue Lake. A commemorative obelisk erected there has an inscription which reads: This obelisk was erected as a memorial to the famous Australian poet. From near this spot in July, 1865 Gordon made his famed leap on horseback over an old post and rail guard fence onto a narrow ledge overlooking the Blue Lake and jumped back again onto the roadway. The foundation stone of the Gordon Memorial Obelisk was laid on 8th July 1887.

Laguna Colorada (Red Lagoon) is a shallow salt lake in the southwest of the altiplano of Bolivia, within Eduardo Avaroa Andean Fauna National Reserve and close to the border with Chile. The lake contains borax islands, whose white color contrasts with the reddish color of its waters, which is caused by red sediments and pigmentation of some algae. Laguna Colorada is one of the Ramsar Wetlands of International Importance under the Ramsar Convention signed in 1971. James's Flamingos abound in the area. Also it is possible to find Andean and Chilean flamingos, but in a minor quantity.

Lake Retba or Lac Rose lies north of the Cap Vert peninsula of Senegal, north east of Dakar. It is so named for its pink waters, caused by cyanobacteria in the water. The color is particularly visible during the dry season. The lake is also known for its high salt content, which, like that of the Dead Sea, allows people to float easily. The lake also has a small salt collecting industry and is often the finishing point of the Dakar Rally. Many salt collectors work 6–7 hours a day in the lake, which has a salt content close to 40%. In order to protect their skin, they rub their skin with "Beurre de Karité" (shea butter, produced from shea nuts obtained from the Shea nut tree), which is an emollient used to avoid tissue damage. This lake was used on a task of the Amazing Race 6 in which teams had to collect salt in a basket from the bottom of the lake floor. The water in Senegal's Lake Retba always seems to have a pinkish hue to it. However, catch it during the dry summer months when the saline levels are high and you will see it turn strawberry pink and sometimes, even red. The good news is that color is not the result of chemicals being dumped in the lake but nature, working its magical tricks! Located in the Cape Vert Peninsula that lies north east of Senegal's capital Dakar, the lake's unusual appearance is caused by a salt-loving green micro alga called Dunaliella salina that resides in the lake, known for its high concentration of the mineral. As you can imagine, very few organisms can survive in such highly saline conditions. The only reason this single-celled organism is able to do so, is because of its ability to create large amounts of Beta-Carotene, that helps protect it against the intense light that reflects off the salt and also gives the algae its dark pink hue. While the color may make the lake appear eerie and unsafe, the micro organism is safe not only to swim amidst, but also, consume - Good news for the locals that are constantly wading in to mine the salt. In fact, the algae are so rich in antioxidants that they are often harvested and used in cosmetics and dietary supplements. This is not the only tiny organism able to transform water hues. In San Diego, CA and many other parts of the world, high concentrations of phytoplankton during certain time of the year, help turn the ocean waters a bright red during the day and an even cooler bioluminescent blue, at night!

Laguna Verde (Green Lagoon) is a salt lake in the southwest of the altiplano of Bolivia, in the Potosí Department, Sur Lípez Province, on the Chilean border at the foot of the volcano Licancabur. Visitors may find some flamingoes dancing in the salt. Its colour is caused by sediments, containing copper minerals. It is elevated some 4,300 m (14,000 ft) above sea level. The laguna verde is well known for its spectacular scenery and hot springs. A small corridor separates the lake from Laguna Blanca.

The Great Blue Hole is a large underwater sinkhole off the coast of Belize. It lies near the center of Lighthouse Reef, a small atoll 70 kilometres (43 mi) from the mainland and Belize City. The hole is circular in shape, over 300 metres (984 ft) across and 124 metres (407 ft) deep. It was formed during several episodes of Quaternary glaciation when sea levels were much lower - the analysis of stalactites found in Great Blue Hole shows that formation has taken place 153,000, 66,000, 60,000, and 15,000 years ago. As the ocean began to rise again, the caves were flooded. The Great Blue Hole is a part of the larger Belize Barrier Reef Reserve System, a World Heritage Site of the United Nations Educational, Scientific and Cultural Organization (UNESCO). This is a popular spot amongst recreational scuba divers, who are lured by the opportunity to dive in crystal-clear water and meet several species of fish, including giant groupers, nurse sharks and several types of reef sharks such as the Caribbean reef shark and the Blacktip shark. Other species of sharks, like the bull shark and hammerheads, have been reported there, but are not regular sightings. Usually, dive trips to the Great Blue Hole are full-day trips, which include one dive in the Blue Hole and two further dives in nearby reefs. Recently diving has also been offered from the island Long Caye in the Lighthouse Reef only a couple of miles away from the Great Blue Hole. They offer 2 dives in the Blue Hole: North side and South side. On-shore caves of similar formation, as large collapsed sinkholes, are well known in Belize and in the Yucatán Peninsula, where they are known as cenotes. This site was made famous by Jacques-Yves Cousteau, who declared it one of the top ten scuba diving sites in the world. In 1971, he brought his ship, the Calypso, to the hole to chart its depths. Investigations by this expedition confirmed the hole's origin as typical karst limestone formations, formed before rises in sea level in at least four stages, leaving ledges at depths of 21, 49, and 91 meters (69, 161 and 299 ft). Stalactites were retrieved from submerged caves, confirming their previous formation above sea level. Some of these stalactites were also off-vertical by 5° in a consistent orientation, thus indicating that there had also been some past geological shift and tilting of the underlying plateau, followed by a long period in the current plane. Initial measured depth of Great Blue Hole was 125 metres (410 ft) which is the most often cited depth up to this day. An expedition by the Cambrian Foundation in 1997 measured the hole's depth as 124 metres (407 ft) at its deepest point. This difference in measurement can be explained by ongoing sedimentation or by imprecision in earlier measurements. The purpose of this expedition was the collection of core samples from the floor of the Blue Hole and documentation of the cave system. To accomplish these tasks, all of the divers had to be certified in cave diving and mixed gases.

The Dead Sea is not a sea at all but a lake made up of 30 percent salt, which turns even the skinniest figures into bouyant blobs on the surface. It's better to just sit there and enjoy it. This salty water is meant to be good for the skin and can help with respiration. Make sure to wear shoes, the salt crystals on the bottom are sharp enough to cut your feet. The Dead Sea, also called the Salt Sea, is a salt lake bordering Jordan to the east and Israel and the West Bank to the west. Its surface and shores are 423 metres (1,388 ft) below sea level, the lowest elevation on the Earth's surface on dry land. The Dead Sea is 377 m (1,237 ft) deep, the deepest hypersaline lake in the world. With 33.7% salinity, it is also one of the world's saltiest bodies of water, though Lake Assal (Djibouti), Garabogazköl and some hypersaline lakes of the McMurdo Dry Valleys in Antarctica (such as Don Juan Pond) have reported higher salinities. It is 8.6 times saltier than the ocean. This salinity makes for a harsh environment in which animals cannot flourish, hence its name. The Dead Sea has attracted visitors from around the Mediterranean basin for thousands of years. Biblically, it was a place of refuge for King David. It was one of the world's first health resorts (for Herod the Great), and it has been the supplier of a wide variety of products, from balms for Egyptian mummification to potash for fertilizers. People also use the salt and the minerals from the Dead Sea to create cosmetics and herbal sachets. In 2009, 1.2 million foreign tourists visited on the Israeli side. The sea has a density of 1.24 kg/L, making swimming difficult but providing a relaxing floating experience. The sea is called "dead" because its high salinity prevents macroscopic aquatic organisms, such as fish and aquatic plants, from living in it, though minuscule quantities of bacteria and microbial fungi are present. In times of flood, the salt content of the Dead Sea can drop from its usual 35% salinity to 30% or lower. The Dead Sea temporarily comes to life in the wake of rainy winters. In 1980, after one such rainy winter, the normally dark blue Dead Sea turned red. Researchers from Hebrew University found the Dead Sea to be teeming with a type of algae called Dunaliella. The Dunaliella in turn nourished carotenoid-containing (red-pigmented) halobacteria, whose presence caused the color change. Since 1980, the Dead Sea basin has been dry and the algae and the bacteria have not returned in measurable numbers. Many animal species live in the mountains surrounding the Dead Sea. Hikers can see camels, ibex, hares, hyraxes, jackals, foxes, and even leopards. Hundreds of bird species inhabit the zone as well. Both Jordan and Israel have established nature reserves around the Dead Sea. The delta of the Jordan River was formerly a veritable jungle of papyrus and palm trees. Flavius Josephus described Jericho as "the most fertile spot in Judea". In Roman and Byzantine times, sugarcane, henna, and sycamore fig all made the lower Jordan valley quite wealthy. One of the most valuable products produced by Jericho was the sap of the balsam tree, which could be made into perfume.

Kelimutu National Park is located on the island of Flores, Indonesia. It consists of a region with hills and mountains, with Mount Kelibara (1,731 m) as its highest peak. Mount Kelimutu, which has the three coloured lakes, is also located in this national park. This natural attraction is a destination for tourists. Mount Kelimutu is a volcano, close to the small town of Moni about 50 km to the east of Ende, Indonesia in central Flores Island of Indonesia. The volcano contains three striking summit crater lakes of varying colors. Tiwu Ata Mbupu (Lake of Old People) is usually blue and is the westernmost of the three lakes. The other two lakes, Tiwu Nuwa Muri Koo Fai (Lake of Young Men and Maidens) and Tiwu Ata Polo (Bewitched or Enchanted Lake) are separated by a shared crater wall and are typically green or red respectively. The lake colors vary on a periodic basis. Subaqueous fumaroles are the probable cause of active upwelling that occurs at the two eastern lakes. The lakes have been a source of minor phreatic eruptions in historical time. The summit of the compound 1639-m-high Kelimutu volcano is elongated two km in a WNW-ESE direction; the older cones of Kelido and Kelibara are located respectively three km to the north and two km to the south. The scenic lakes are a popular tourist destination. Kelimutu is also of interest to geologists because the three lakes are different colors yet are at the crest of the same volcano . According to the local officer at Kelimutu National Park, the colour changes as a result of chemical reactions resulting from the minerals contained in the lake perhaps triggered by volcano gas activity. Kawah Putih lake in West Java, south of Bandung, is another crater lake in Indonesia with some similarities to the lakes at Kelimutu. Some endagered plant species are protected in this national park, such as: Toona spp., Anthocephalus cadamba, Canarium spp., Diospyros ferra, Alstonis scholaris, Schleichera oleosa, Casuarina equisetifolia and Anaphalis javanica. Some endangered animals can also be found here, such as: Javan Rusa, Wild boar sp., Red Junglefowl, Elanus sp. and Drongo sp. (Dicrurus sulphurea). The four endemic mammals in the park include two montane rodents: Bunomys naso and Hainald's Rat (Rattus hainaldi). In this area, there is also an arboretum, a mini jungle (4,5 ha) represent flora biodiversity of Kelimutu National Park. The arboterum consists of 78 types of tree plants which are grouped into 36 families. Some of the Kelimutu's endemic flora collections are uta onga (Begonia kelimutuensis), turuwara (Rhododendron renschianum), and arngoni (Vaccinium varingiaefolium). The closest airports are Maumere, and Ende. There are regular flights to Maumere from Bali. The drive from Maumere to Moni, the town at the base of Kelimutu where accommodation is available, takes about 3 hours.

The Nanda Blue Hole (also known as Jackie's Blue Hole or Jacquie's Blue Hole) is a beautiful blue hole on the island of Espiritu Santo in Vanuatu. The water is a magical deep blue that is surrounded by natural green forest. Blue Holes are an amazing natural creation, formed by springs of fresh pure water rising to the surface cutting out a deep hole in the limestone.The area around the blue hole have been specifically designed for day trippers, with a large under cover area, a bar with beer and soft drinks, picnic area and a swing with a platform. Located half way between Luganville and Champayne Beach along the East Coast Road at Natawa. The Blue hole is close to several resorts including Turtle Bay Lodge and Oyster Island Resort.

Ever wanted to go diving in a crack between two continents in some of the clearest water on Earth? In the Icelands Þingvellir National Park ever-widening Almannagjá canyon, you can walk in the seam of the Eurasian and North American plates as they slowly move apart—or you can dive into the crack between continents in the Silfra Rift in Lake Þingvellir. Silfra, by virtue of its location in the Þingvallavatn, contains clear, cold water that attracts scuba divers drawn to its high visibility and geological importance; divers are literally swimming between continents. The rift claims a shallow depth nearest to the bank, but deepens and widens further out. The rift offers amazing visibility and has been placed on the top 3 diving destinations list by multiple publications. The waters are so clear that many divers are said to lose all sense of depth and even experience vertigo. The visibility reaches end-of-sight and is rated at 150 to 300 meters. The water is 50 to 100 years old once it reaches the lake from the melting glacier through the lava field, and is drinkable.

The Red Beach is located in the Liaohe River Delta, about 30 kilometer southwest of Panjin City in China. The Shuangtai Hekou Nature Reserve has been setup to protect this unusual area. The National Nature Reserve area covering 20 square kilometres. The beach gets its name from its appearance, which is caused by a type of sea weed that flourishes in the saline-alkali soil. The weed that start growing during April or May remains green during the summer. In autumn, this weed turns flaming red, and the beach looks as if it was covered by an infinite red carpet that creates a rare red sea landscape. Most of the Red Beach is a nature reserve and closed to the public. Only a small, remote, section is open for tourists. This area is also a key habitat and a way station for migratory birds on their East Asia-Australia route. A local delicasy is crabs. Most tours of the Red Beach will include a change to sample one of these crustations yourself. There are seven trains leaving Beijing a day that stop in Panjin so getting there by train is the easiest way. The fast trains take just under three and a half hours and the slower trains take five to six hours. Once in Panjin, you can take local buses or taxis to the Read Sea area.

Diving is forbidden in the green lake since a few years. Nevertheless it is still a breathtaking natural sight! Grüner See (Green Lake) is a lake in Styria, Austria near the town of Tragöß. The lake is surrounded by the Hochschwab mountains and forests. The name “Green Lake” originated because of its emerald green water. The clean and clear water comes from the snowmelt from the karst mountains and has a temperature of 6-8°C (42.8-46.4°F). During the winter, the lake is only 1–2 m deep and the surrounding area is used as a county park. However, during the spring, when the temperature rises and the water melts the basin of land below the mountains fill with water. The lake reaches its maximum depth of around 12 m from mid-May to June and is claimed to look the most beautiful at this time. In July, the water begins to recede. The lake supports a variety of fauna such as snails, water fleas (Daphnia pulex), small crabs, fly larvae, and different species of trout (Salmo). The flora is not abundant because of the rocky bottom of the lake. Furthermore, the lake’s depth is variable since its inflow comes from snowmelt. The lake is popular among divers who can observe the green meadows in the edge zone of the lake particularly in June when the water is at its highest. A bridge and a bench can also be found underwater.

Huanglong is a scenic and historic interest area in Songpan County in the northwest part of Sichuan, China. It is located in the southern part of the Minshan mountain range, 150 km north-northwest of the capital Chengdu. This area is known for its colorful pools formed by calcite deposits, especially in Huanglonggou (Yellow Dragon Gully), as well as diverse forest ecosystems, snow-capped peaks, waterfalls and hot springs. Huanglong is also home to many endangered species including the Giant Panda and the Sichuan Golden Snub-nosed Monkey. Huanglong was declared a World Heritage Site by UNESCO in 1992. Due to thousands of years of geological evolution, Huanglong consists of numerous unique landscapes of geological landforms. Glacial revolution, terrane structure, stratum of carbonic acid rock, tufa water and climatic conditions such as artic-alpine sun light have created this world-famous travertine landscape. These accumulated travertine landscapes and fascinating pools are Huanglong's main attraction. The total length of the travertine is 3.6km and it is thought to look like a huge golden dragon wheeling through the snow-capped mountains of the valley. The main landscapes are travertine banks, amazingly colourful ponds and travertine waterfalls and caves. The main body of water starts from the ancient Buddhist/Benbo temple at the top of the valley and ends at Xishen Cave Waterfall in the north with a length of 2.5km and a width of 30 – 170m. The colours of Huanglong’s waters consist of yellows, greens, blues and browns. The flowing water appears golden in the sun. Known to the locals as “Golden Sand on Earth,” the Huanglong travertine bank is the largest in the world.

The Río Celeste (Light Blue River) is one of Costa Rica’s most spectacular rivers. Located in the northern reaches of the country within the Tenorio Volcano National Park. This awe-inspiring river turns sky blue due to the emanation of sulfur from the volcano and precipitation of calcium carbonate. Traveling upstream where one can see the waters stretch into an impressing waterfall. Further up one will find calm lagoons and a littler farther up, one will discover the source in itself a marvel; the place from which the waters get their lively and original color of the sky. Getting to the river will require a drive on a rough 20+ km road but its worth it in the end. Get a 4 x 4 to really enjoy the area although a regular car can get here from the main road but not the new short cut from highway 6 which reduces the journey from Liberia significantly .

Spotted Lake — known as Lake Khiluk in the Nsyilxcən language — is a saline endorheic alkali lake located northwest of Osoyoos in the eastern Similkameen Valley of British Columbia, Canada, accessed via Highway 3. Spotted Lake is richly concentrated with various minerals. It contains dense deposits of magnesium sulfate, calcium and sodium sulphates. It also contains high concentrations of eight other minerals and lower amounts of silver and titanium. Most of the water in the lake evaporates over the summer, revealing colourful mineral deposits. Large "spots" on the lake appear and are coloured according to the mineral composition and seasonal amount of precipitation. Magnesium sulfate, which crystallizes in the summer, is a major contributor to spot colour. In the summer, remaining minerals in the lake harden to form natural "walkways" around and between the spots. Originally named in the Nsyilxcən language of the Syilx First Nation of the Okanagan Valley as Kłlil’xᵂ, Spotted Lake was for centuries, and still remains, revered as a sacred site thought to provide therapeutic waters. During World War I, the minerals of Spotted Lake were used in manufacturing ammunition. Later, the area came under the control of the Ernest Smith Family for a term of about 40 years. In 1979, Smith attempted to create interest in a spa at the lake. The First Nations responded with an effort to buy the lake, then in October 2001, struck a deal by purchasing 22 hectares (54 acres) of land for a total of $720,000, and contributed about 20% of the cost. The Indian Affairs Department paid the remainder. Today, there is a roadside sign telling visitors that the lake is a cultural and ecologically sensitive area, and a traditional medicine lake for the Okanagan Syilx people. The lake can be viewed from the fence that has been erected for protection from the liabilities of public access.

Pink Lake is a salt lake in the Goldfields-Esperance region of Western Australia. During certain time sof the yar the lake turned pink due the algae that live in the lake which gives it unusual complexion. The lake is not always pink in colour but the distinctive colour of the water when the lake is pink is a result of the green alga Dunaliella salina, halobacterium Halobacteria cutirubrum, and/or high concentration of brine prawn. Once the lake water reaches a salinity level greater than that of sea water, the temperature is high enough and adequate light conditions are provided, the alga begins to accumulate the red pigment beta carotene. The pink halobacteria grow in the salt crust at the bottom of the lake and the colour of the lake is a result of the balance between D. salina and H. cutirubrum. The lake has been identified by BirdLife International as an Important Bird Area (IBA) because it usually supports significant numbers of Hooded Plovers and sometimes over 1% of the world population of Banded Stilts. It lies about 3 kilometres (2 mi) west of Esperance and is bounded to the East by the South Coast Highway.

Abraham Lake is an artificial lake on North Saskatchewan River in western Alberta, Canada. A rare phenomenon on the lake is the bubbles frozen underneath the surface. The plants on the lake bed releases methane gas and methane gets frozen once coming close enough to much colder lake surface and they keep stacking up below once the weather gets colder and colder during the course of winter. It was built on the upper course of the North Saskatchewan River, in the foothills of the Canadian Rockies. It lines David Thompson Highway betweenSaskatchewan River Crossing and Nordegg. Abraham Lake was created in 1972, with the construction of the Bighorn Dam. The Government of Alberta sponsored a contest to name the lake in February 1972, during the final stages of construction of the Bighorn dam. Students across the province were asked to submit names taking into consideration "historical significance, prominent persons, geography and topography, and the value of the lake." It was named for Silas Abraham, an inhabitant of the Saskatchewan River valley in the nineteenth century. Although man-made, the lake has the blue color of other glacial lakes in the Rocky Mountains, which is caused by rock flour as in other glacial lakes. The Cline River Heliport is located on the western shore of the lake. Abraham Lake has a surface area of 53.7 km2 (20.7 sq mi) and a length of 32 km (20 mi).

Dominica's Boiling Lake is situated in the Morne Trois Pitons National Park - Dominica's World Heritage site. It is a flooded fumarole 6.5 miles (10.5 km) east of Roseau, Dominica. It is filled with bubbling greyish-blue water that is usually enveloped in a cloud of vapour. The lake is approximately 200 ft (60 m) across. There is no road leading directly to the lake. It is approximately a 13 kilometer hike to the lake from the nearest road, passing sulfur springs, over mountains and through gorges along the way. The first recorded sighting of the lake was in 1870 by Mr. Watt and Dr. Nicholls, two Englishmen working in Dominica at that time. In 1875, Mr. H. Prestoe, a government botanist, and Dr. Nicholls were commissioned to investigate this natural phenomenon. They measured the water temperature and found it to range from 180 to 197 degrees Fahrenheit (82 to 91.5 Celsius) along the edges, but could not measure the temperature at the centre where the lake is actively boiling. They recorded the depth to be greater than 195 ft (59 m). Periodically, there have been fluctuations in the level and activity of the lake. It was all but empty in June 2006, however as of January 2009 the lake is full and boiling vigorously. On July 6, 2007, adventure-film maker George Kourounis became the first person to ever cross the boiling lake from above, suspended by ropes over the most violently boiling section. This event was filmed for the TV series Angry Planet. Dominica's Boiling Lake is the second largest hot spring in the world. The largest is Frying Pan Lake, located in Waimangu Valley near Rotorua, New Zealand.

Blood Falls is an outflow of an iron oxide-tainted plume of saltwater, flowing from the tongue of the Taylor Glacier onto the ice-covered surface of West Lake Bonney in the Taylor Valley of the McMurdo Dry Valleys in Victoria Land, East Antarctica. Iron-rich hypersaline water sporadically emerges from small fissures in the ice cascades. The saltwater source is a subglacial pool of unknown size overlain by about 400 m of ice at several km from its tiny outlet at Blood Falls. The reddish deposit was found in 1911 by the Australian geologist Griffith Taylor, who first explored the valley that bears his name. The Antarctica pioneers first attributed the red color to red algae, but later it was proven to be due only to iron oxides. Poorly soluble hydrous ferric oxides are deposited at the surface of ice after the ferrous ions present in the unfrozen saltwater are oxidized in contact with atmospheric oxygen. The more soluble ferrous ions initially are dissolved in old seawater trapped in an ancient pocket remaining from the Antarctic Ocean when a fjord was isolated by the glacier in its progression during the Miocene period, some 5 million years ago when the sea level was higher than today. Unlike most Antarctic glaciers, the Taylor glacier is not frozen to the bedrock, probably, because of the presence of salts concentrated by the crystallization of the ancient seawater imprisoned below it. Salt cryo-concentration occurred in the deep relict seawater when pure ice crystallised and expelled its dissolved salts as it cooled down because of the heat exchange of the captive liquid seawater with the enormous ice mass of the glacier. As a consequence, the trapped seawater was concentrated in brines with a salinity two to three times that of the mean ocean water. A second mechanism sometimes also explaining the formation of hypersaline brines is the water evaporation of surface lakes directly exposed to the very dry polar atmosphere in the McMurdo Dry Valleys. The analyses of stable isotopes of water allow, in principle, to distinguish between both processes as long as there is no mixing between differently formed brines. Hypersaline fluid, sampled fortuitously through a crack in the ice, was oxygen-free and rich in sulfate and ferrous ion. Sulfate is a remnant geochemical signature of marine conditions while soluble divalent iron likely was liberated under reducing conditions from the subglacial bedrock minerals weathered by microbial activity.

Red Lake is a sinkhole containing a karst lake near the city of Imotski, Croatia. It is known for its numerous caves and remarkably high cliffs, reaching over 241 metres above normal water level and continuing below the water level. The total explored depth of this sinkhole is approximately 530 metres with a volume of roughly 25-30 million cubic meters, thus it is the third largest sinkhole in the world. Water drains out of the basin through underground waterways that descend below the level of the lake floor. The sinkhole is named after the reddish-brown color of the surrounding cliffs, colored by iron oxides. Like the nearby Blue Lake, it is presumed that the lake emerged when the ceiling of a large cave hall collapsed. The lake is a habitat of the near-endemic fish Delminichthys adspersus (Heckel, 1843). In the dry period of the year this fish can be occasionally seen in surrounding springs, rivers and lakes, suggesting that there is an underground connection between Red Lake and other water bodies.