10 Longest Natural Arches in The World

These known 10 longest natural arches in the world are measured by the Natural Arch and Bridge Society (NABS). The NABS states that the rankings may change because of the more accurate measurement techniques, and the new-find arches in the future.

1. Xian Ren Qiao, 400 feet (121.9 meters)

Fairy Bridge from downstream. Photo by Gunter Welz, via The Natural Arch and Bridge Society

Xian Ren Qiao, literally means Fairy Bridge, is located in northern Guangxi Province, China. It is a meander natural arch carved through limestone karst by the flowing water of the Buliu River. Xian Ren Qiao has the longest recorded span in the world, with 400 feet (121.9 meters) in length. Span measured by NABS in 2010.

2. Zhijin Natural Bridge, 340 feet (103.6 meters)

Zhijin Natural Bridge is located in the Guizhou Zhijin Cave Scenic Area in Zhijin County, Guizhou Province, China. Tourist area Zhijin Cave itself is considered to be the most magnificent cave in China. Zhijin Natural Bridge is the second-longest natural arch with a span of 340 feet (103.6 meters). Span measured by NABS member Gunter Welz in 2015.

3. Jiangzhou Immortal Bridge, 280-340 feet

Jiangzhou Immortal Bridge. Photo by Rosysea. CC by 3.0

Jiangzhou Immortal Bridge is a meander natural bridge connecting the two mountains. It is located in Jiangzhou, Guangxi Province, China. A sign by the arch claims it as the second longest natural arch in the world. This may be true, because an upper bound can be placed at around 340 feet, and a lower bound can be placed at around 280 feet.

However, NABS states that this measurement cannot be confirmed at the present time because of the conflicting information about the arch.

4. Dachuandong Arch, 300 feet (91.4 meters)

Dachuandong Arch is located near the village of Si Lian in Guizhou Province, China. Dachuandong Arch has a span of 300 feet (91.4 meters), and a height of 135 feet. Span measured by NABS member Gunter Welz in 2015.

5. Landscape Arch, 290 feet (88.4 meters)

Landscape Arch. Photo by Cacophony. CC by 3.0

Landscape Arch is located in the Devils Garden area of Arches National Park in Utah, United States. It has a span of 290 feet (88.4 meters) according to measurement made by NABS in 2004. Landscape Arch is the longest natural rock arch that is considered old and near the end of its lifecycle.

Landscape Arch could collapse at any time. The thinnest section of the arch is only 6 feet thick, yet it supports a 290 feet long rock. Three rockfall occured in the 1990s. Due to these rockfall events, the Park Service has closed the trail underneath the arch.

6. Kolob Arch, 287 feet (87.5 meters)

Kolob Arch is an adult alcove natural arch located in Zion National Park, Utah. It was formerly considered longer than Landscape Arch according to the measurement by the Society. However, the NABS took a very accurate measurement in October 2006 and found that Kolob Arch has a span of 287 feet, only 3 feet shorter than the span of Landscape Arch.

7. Qingxudong Arch, 251 feet (76.5 meters)

Qingxudong Arch is located near of the village of Yang Chang Ba in Guizhou Province, China. Qingxudong Arch has a span of 251 feet (76.5 meters) and a height of 246 feet. Span measured by NABS member Gunter Welz in 2015.

8. Aloba Arch, 250 feet (76.2 meters)

Aloba Arch is the magnificent seldom seen natural arch located in the Ennedi Plateau of the Sahara Desert in the northeast part of the country of Chad. Aloba Arch is ranked the 8th longest known natural arch with a span of around 250 feet. But it is considered to be one of the tallest known arches in the world with 394 feet tall.

According to NABS standards, less accurate means in measurement were necessary due to a direct measurement was not possible.

9. Morning Glory Natural Bridge, 243 feet (74.1 meters)

Though it’s named Morning Glory Natural Bridge, but actually it is a very large alcove arch, not a natural bridge. Morning Glory Natural Bridge is located in Negro Bill Canyon near Moab, Utah. The span first measured by Robert Vreeland and reported it to be 243 feet. This measurement then has been confirmed by Jay Wilbur of NABS.

10. Gaotun Natural Bridge, 240 feet (73.2 meters)

Gaotun Natural Bridge, or Tiansheng Qiao in Chinese, is a waterfall natural bridge eroded through limestone karst. It is located in Bazhou He Scenic Area near the town of Gaotun in Liping County, Guizhou Province, China. Gaotun Natural Bridge has a span of 240 feet, reported by NABS member Gunter Welz in October 2010.

Source: http://www.naturalarches.org/

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10 Ancient Lakes That Still Exist on Earth Today

Ancient lakes are lakes that have consistently carried water for more than one million years. These lakes continue to persist because of the plate tectonics in an active rift zone creates extremely deep lakes and difficult to fill with sediment naturally.

So here is the list of 10 Ancient Lakes That Still Exist on Earth Today:

1. Lake Baikal, Russia

There are few reasons that make Lake Baikal as one of the most notable lakes in the world:

- Lake Baikal was formed as an ancient rift valley by the Baikal Rift Zone 25–30 million years ago, makes it the oldest lake in the world today,

- Lake Baikal has the typical crescent shape with a surface area of 12,248 square miles (31,722 km²),

- Lake Baikal is the clearest and the largest freshwater lake by volume which contains 22–23% of the fresh surface water on earth,

- Lake Baikal is the deepest lake with a maximum depth of 1,642 meters,

- Lake Baikal contains 27 islands; with the largest is Olkhon (45 miles long). Olkhon is the third-largest lake-bound island in the world.

- Lake Baikal was declared as World Heritage Site by UNESCO in 1996.

2. Lake Zaysan, Kazakhstan

Lake Zaysan. Photo by Dmitry A. Mottl. CC by 3.0

Lake Zaysan is considered to be even older than Lake Baikal, at least 65 million years old. But its exact age is labelled with some uncertainty. Some geological studies of the Zaysan basin have been reviewed, but it is still difficult to find the direct indication of its age.

Lake Zaysan is a freshwater lake with a surface area of 700 square miles (1,810 km²), which makes it the largest lake in the East Kazakhstan Region. It has a maximum depth of 15 meters, but the lake has risen 6 meters above its natural level since the construction of the Bukhtarma dam on the Irtysh downstream from the Zaysan.

3. Lake Maracaibo, Venezuela

Lake Maracaibo is one of the oldest lakes on Earth at 20–36 million years old, and was once the largest lake in South America at 5,100 square miles (13,210 km²). The geological record shows that it has been a true lake in the past, but now it is considered a large brackish tidal bay that is connected to the Gulf of Venezuela by Tablazo Strait.

Alonso de Ojeda was the first European to discover the bay in 1499, on a voyage with Amerigo Vespucci. According to legend, Ojeda's expedition found groups of indigenous stilt houses built on water. These stilt houses reminded Vespucci of the city of Venice, so he named the region Venezuela (which in Spanish means little Venice).

4. Lake Tanganyika, East Africa

Lake Tanganyika. Photo: www.zambiatourism.com

Lake Tanganyika is the ancient freshwater lake with its three basins are of different ages. The central has been estimated around 9-12 million years, the northern 7-8 million years, and the southern 2-4 million years old. One of the river flowing into the lake is Malagarasi river which enters the east side of Lake Tanganyika. The Malagarasi river is older than Lake Tanganyika.

Lake Tanganyika is the largest rift valley lake in Africa with a surface area of 12,700 square miles (32,900 km²). The lake is divided among four countries: Burundi, Democratic Republic of the Congo, Tanzania, and Zambia. Lake Tanganyika is also the second largest lake by volume in the world after Lake Baikal in Siberia.

5. Lake Malawi, East Africa

Lake Malawi. Photo by Noel Peries, via www.maggieinafrica.com

Lake Malawi, also known as Lake Nyasa or Lago Niassa, is the major meromictic lake which has a total surface area of around 11,400 square miles (29,600 km²). Meromictic lake means that its water layers do not mix. The permanent stratification of the water and the oxic-anoxic boundary relating to oxygen in the water are maintained by moderately thermal gradients and small chemical.

Ancient Lake Malawi has been tipically estimated to be 1-2 million years old which formed by a divergent plate tectonics boundary. However, the recent evidence has been estimated that the basin started to form about 8.6 million years ago and deep-water condition first occurred 4.5 million years ago.

6. Caspian Sea, Eurasia

Caspian Sea. Photo: via wikipedia.org

The Caspian Sea, located between Europe and Asia, is generally regarded as the largest inland endorheic salt lake. However, the ancient inhabitants always regarded Caspian as a sea because of its large size and saltiness.

Caspian sea has a surface area of around 143,200 square miles (371,000 km²), and a volume of 78,200 km³. It also has a salinity of about one third of the salinity of most oceans, approximately 1.2%. Though today the Caspian Sea is a freshwater lake in its northern portions due to the current inflow of fresh water.

The Caspian Sea, is believed to be one of the remnants of the ancient Paratethys Sea. The other remnants are Black Sea, Lake Urmia, and Namak Lake. About 5.5 million years ago, Caspian Sea became landlocked because of the tectonic movement and a fall in sea level.

7. Lake Ohrid, Balkans

Lake Ohrid. Photo by: Dave Proffer on Flickr, CC by 3.0

Lake Ohrid has been estimated to be around five million years old, and belongs to a group of Dessaret basins that originated from a geotectonic depression during the Pliocene epoch. However, Macedonian media reported in 2008 that international experts will be researching the lake to determine its age.

Lake Ohrid is the deepest lake of the Balkans with a maximum depth of 288 meters, and covers an area of 358 square kilometers. It is located between southwestern Macedonia and eastern Albania. Around two thirds part of the lake belongs to the Republic of Macedonia, and the rest belongs to Albania.

In 1979, UNESCO declared Lake Ohrid as a World Heritage Site. In 2010, NASA decided to name a hydrocarbon lake on the Saturnian moon Titan after Lake Ohrid: Ohrid Lacus. And in 2014, UNESCO added the Ohrid-Prespa Transboundary Reserve between Albania and Macedonia to UNESCO's World Network of Biosphere Reserves.

8. Lake Biwa, Japan

Lake Biwa is the largest freshwater ancient lake in Japan with the surface area of  258.8 square miles (670.3 km²). It is also one of the oldest lake in the world dating to around 4 million years ago. According to Naturalists, Lake Biwa is of tectonic origin which houses over 1000 species and subspecies, including around 60 endemic.

Lake Biwa, which formerly known as the Awaumi (Freshwater Sea), also houses an important archaeological site of Jōmon period that goes back to the beginning of the Initial Jōmon period (ca. 9300 BP). The site lies at a depth of 2m to 3m from the bottom, near the southern end of Lake Biwa.

9. Lake Lanao, Philippines 

Lake Lanao. Photo: lanaodelsur.gov.ph

Lake Lanao is the second largest lake in the Philippines with a surface area of 130 square miles (340 km²). This rift lake is counted as one of the 15 ancient lakes in the world, which was formed by the collapse of a large volcano and the tectonic-volcanic damming of a basin between two mountain ranges.

There is a myth among the Meranaw tribe that describes the formation of Lake Lanao. The myth said that a group of angels created the hole in order to removed the vast population of Mantapoli. The hole was filled with water and threatened to drown the rest of the world. To prevent this, the angels asked the help of the Four Winds to gouge out an outlet. The hole then formed into Lake Lanao and the outlet formed into the Agus river.

10. Lake Titicaca, South America

Lake Titicaca is a large mountain lake that covers area of 3,232 square miles (8,372 km²). It is the largest lake in South America by surface area and by volume of water. Note that although Lake Maracaibo has a larger surface area, but now it is considered as a tidal bay, not a lake.

Lake Titicaca has a surface elevation of 3,812 meters and is often called the "highest navigable lake" in the world. However, its water level dropped constantly since the 2000 caused by the shortened rainy seasons, and its biodiversity is threatened by water pollution. Thus in 2012, the Global Nature Fund nominated the lake as "Threatened Lake of the Year".

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10 Largest Saltwater Lakes In The World

A saltwater lake, also known as a saline lake, is a landlocked body of water, having no natural outlet to the sea, and containing a high concentration of salts. Some of the saltwater lakes are regarded as seas due to their high salt content and their large size.

Caspian Sea. Photo: via wikipedia.org

1. Caspian Sea, 371,000 km²

The Caspian Sea, located between Europe and Asia, is generally regarded as the largest inland endorheic salt lake. However, the ancient inhabitants always regarded Caspian as a sea because of its large size and saltiness.

Caspian sea has a surface area of around 143,200 square miles (371,000 km²). It also has a salinity of about one third of the salinity of most oceans, approximately 1.2%. Though today the Caspian Sea is a freshwater lake in its northern portions due to the current inflow of fresh water.

The Caspian Sea, is believed to be one of the remnants of the ancient Paratethys Sea. The other remnants are Black Sea, Lake Urmia, and Namak Lake. About 5.5 million years ago, Caspian Sea became landlocked because of the tectonic movement and a fall in sea level.

2. Aral Sea, 17,160 km²

The Aral Sea  was an endorheic lake located between Uzbekistan in the south and Kazakhstan in the north. It used to be the fourth largest lake in the world, with an area of 68,000 km² (26,300 sq mi). But due to the 1960s Soviet irrigation projects, the Aral Sea has been shrinking, and splitting into four lakes. The Aral Sea’s shrinking was "one of the planet's worst environmental disasters".

In 2004, the Aral Sea's surface area was only 25% of its original size (17,160 km²). By 2007, the area of the sea had further shrunk to 10% of its original size. In August 2014, NASA revealed that the eastern basin of the Aral Sea had completely dried up, and that part has created the Aralkum Desert.

3. Lake Eyre, 9,500 km²

Lake Eyre, also known as Kati Thanda–Lake Eyre, is an endorheic lake contains the lowest natural point in Australia, also the largest lake in Australia with an area of 9,500 km² (3,668 sq mi) when it fills. When the lake is full, around midday the water surface can become very flat and virtually impossible to see. But when saturated, the lake shows pink colouration due to the presence of algae.

Every three years, typically  a 1.5 m flood occurs and the salinity in the lake increases resulting in a massive fish kill But the lake is almost fresh when recently flooded, and native freshwater fish can survive in it.

4. Lake Torrens, 5,745 km²

Lake Torrens is an ephemeral endorheic saltwater lake located within the boundaries of Lake Torrens National Park in central South Australia. When Lake Torrens filled with water after extreme rainfall events, the lake can encompasses an area of 5,745 km² (2,218 sq mi) and flow out through the Pirie-Torrens Corridor to the Spencer Gulf.

The lake water was fresh to brackish around 35,000 years ago, but since then it has become increasingly saline. Since at least 1995, Lake Torrens is part of the Inland Saline Lakes which has been listed in the Directory of Important Wetlands in Australia. And since 1991, the full extent of Lake Torrens has been protected as a national park under the National Parks and Wildlife Act 1972.

5. Lake Urmia, 5,200 km²

Lake Urmia is an endorheic saltwater lake in Iran, west of the southern portion of the Caspian Sea. At its greatest extent, it was once the largest salt lake on Earth, with a surface area of around 5,200 km² (2,000 sq mi). But the lake has shrunk to 10% of its original size due to the pumping of groundwater, dam construction, and climate change.

Lake Urmia had approximately 102 islands, with the largest island was Shahi Island. But when the lake level dropped, Shahi Island became a peninsula connected to the eastern shore. Lake Urmia, along with its islands, is now protected as a national park by the Iranian Department of Environment.

6. Great Salt Lake, 4,400 km²

The Great Salt Lake, located in the U.S. state of Utah, is the largest endorheic salt lake in the Western Hemisphere, with the average surface area of around 4,400 km² (1,700 square miles). The lake's size is fluctuative due to its shallowness, the water level can rise during high precipitation years and fall dramatically in dry years.

The lake is the largest remnant of a prehistoric pluvial lake called Lake Bonneville that covered much of present-day western Utah during the ice ages of the Pleistocene Epoch. Great Salt Lake has very high salt content that is far saltier than seawater. Due to its high salt content, swimming in this lake is similar to floating.

7. Qinghai Lake, 4,317 km²

Qinghai Lake or Tso Ngonpo or Koko Nor is the salt lake located on an endorheic basin in Qinghai province, China. It used to be connected to the Yellow River, but then became isolated from the Yellow River about 150,000 years ago. As measured in 2008, Qinghai Lake has a surface area of 4,317 km² (1,667 sq mi).

Qinghai Lake has fluctuated in size, the water surface has shrunk by 312 km² over the last three decades. Its loss of surface area are due to land reclamations and natural causes. Qinghai Lake has been splitting into half a dozen lakes since the 1960s, three of them are: Gahai Lake, Shadao Lake, and Haiyan Lake.

8. Lake Van, 3,755 km²

Lake Van is one of the largest endorheic salt lakes in the world, lies in the far east of Turkey. It has a surface area of 3,755 km² (1,450 sq mi), and four islands on it. Lake Van has no outlet flow because its outlet was blocked at some time during the ancient time of Pleistocene.

In 2017, a team of archaeologists and independent divers reported the discovery of a large underwater fortress spanning around one kilometer. Based on their visual assessments, the team estimates that this fortress was constructed near the shores of Lake Van during the Urartian period, and had slowly become submerged over the millennia by the gradually rising lake.

9. Lake Bakhtegan, 3,500 km²

Lake Bakhtegan was a salt lake in Fars Province, southern Iran. With a surface area of 3,500 km², it was the second-largest lake in Iran. The lake was fed mostly by the Kor River. But the several dams construction on the river had significantly reduced water volume of the lake.

10. Lake Mackay, 3,494 km²

Lake Mackay is the largest salt lakes in Western Australia and the Northern Territory, with a surface area of 3,494 km² (1,349 sq mi). The lake was named after its European discoverer, Donald George Mackay. But it is also known as Wilkinkarra to the local indigenous population.

The darker areas of the lake-bed indicate some form of algae, and the lowest elevations where pooling of water occurs. While the white reflective surface is produced by evaporation that cause salts and other minerals are carried to the surface through capillary action.

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10 Largest Lakes On Earth by Surface Area

This list includes both salt lakes and freshwater lakes that have the largest surface area on earth. The area of some lakes can vary over time depending on the seasons, climate changes, and human causes. This list does not include extraterrestrial lakes, i.e lakes on moon or other planet.

1. Caspian Sea, 371,000 km²

The Caspian Sea, located between Europe and Asia, is generally regarded as the largest inland endorheic salt lake. However, the ancient inhabitants always regarded Caspian as a sea because of its large size and saltiness.

Caspian sea has a surface area of around 143,200 sq mi (371,000 km²), and a volume of 78,200 km³. It also has a salinity of about a third of the salinity of most seawater, approximately 1.2%.

The Caspian Sea, is believed to be one of the remnants of the ancient Paratethys Sea. The other remnants are Black Sea, Lake Urmia, and Namak Lake. About 5.5 million years ago, Caspian Sea became landlocked because of the tectonic movement and a fall in sea level.

2. Lake Superior, 82,100 km²

Lake Superior is the largest of the group Great Lakes of North America, also the largest freshwater lake in the world by surface area (if Lake Michigan and Lake Huron are taken separately). It has a vast area of 82,103 km² (31,700 sq mi), is fed by more than 200 rivers, and empties into Lake Huron via the Soo Locks and the St. Marys River.

Though there is no certain evidence that shows the actual age of Lake Superior, but the rocks at the northern shore of Lake Superior date back to the early history of the earth.

3. Lake Victoria, 68,870 km²

Lake Victoria has a surface area of around 68,800 km²(26,600 sq mi). This large area makes Lake Victoria the largest lake in Africa, the largest tropical lake in the world, and the second-largest fresh water lake in the world.

Lake Victoria is one of the African Great Lakes. It occupies a shallow depression in Africa, and is divided among three countries: Kenya, Uganda, and Tanzania. The lake is fed primarily from direct rainfall and thousands of small streams. Its only outflow is the Nile River near Jinja, Uganda, on the lake's northern shore.

4. Lake Huron, 59, 590 km²

Lake Huron is one of the five Great Lakes of North America, also the second-largest of the Great Lakes group by surface area, which covers 59,590 km2 (23,007 sq mi). Lake Huron is the home for about 30,000 islands, and has the largest shore line length of any of the Great Lakes with a number of large cities on it.

Lake Huron is a freshwater lake that was formed by melting ice as the continental glaciers retreated toward the end of the last ice age. In the last century, its ecology has undergone drastic changes. It has suffered because of the introduction of new invasive species. Experts estimated that these recent changes may be attributable to the new exotic species.

Lake Michigan-Huron. Photo: via wikipedia.org

5. Lake Michigan, 58,026 km²

Lake Michigan is the largest lake entirely contained within one country by surface area of 58,026 km² (22,404 sq mi). It lies in the region known as the American Midwest. Lake Michigan has many beaches, which region is often called as the Third Coast of the United States.

Lake Michigan and Lake Huron hydrologically are the same body of water that is sometimes called Lake Michigan-Huron, part of the Great Lakes Waterway. The dividing line between them is the Straits of Mackinac, also known as Mackinac Bridge. If counted together, Lake Michigan–Huron is the largest fresh water lake in the world by surface area.

6. Lake Tanganyika, 32,600 km²

Lake Tanganyika. Photo: www.zambiatourism.com

Lake Tanganyika is the ancient freshwater lake with its three basins are of different ages. The central has been estimated around 9-12 million years, the northern 7-8 million years, and the southern 2-4 million years old. One of the river flowing into the lake is Malagarasi river which enters the east side of Lake Tanganyika. The Malagarasi river is older than Lake Tanganyika.

Lake Tanganyika is the largest rift valley lake in Africa with a surface area of 12,700 square miles (32,900 km²). The lake is divided among four countries: Burundi, Democratic Republic of the Congo, Tanzania, and Zambia. Lake Tanganyika is also the second largest lake by volume in the world after Lake Baikal in Siberia.

7. Lake Baikal, 31,500 km²

Lake Baikal is a continental rift lake located in Siberia, Russia. There are few reasons that make Lake Baikal as one of the most notable lakes in the world:

- Lake Baikal was formed as an ancient rift valley by the Baikal Rift Zone 25–30 million years ago, makes it the oldest lake in the world today,

- Lake Baikal has the typical crescent shape with a surface area of 12,248 square miles (31,722 km²),

- Lake Baikal is the clearest and the largest freshwater lake by volume which contains 22–23% of the fresh surface water on earth,

- Lake Baikal is the deepest lake with a maximum depth of 1,642 meters,

- Lake Baikal contains 27 islands; with the largest is Olkhon (45 miles long). Olkhon is the third-largest lake-bound island in the world.

- Lake Baikal was declared as World Heritage Site by UNESCO in 1996.

8. Great Bear Lake, 31,153 km²

The Great Bear Lake is the largest lake entirely in Canada, and the fourth largest in North America with surface area of 31,153 km² (12,028 sq mi).

Great Bear Lake was part of Glacial Lake McConnell in the pre-glacial valleys that during the Pleistocene it was reshaped by erosional ice. There are five arms of Great Bear Lake: the Dease Arm (northeast), the Smith Arm (northwest), the McTavish Arm (southeast), and the Keith Arm (southwest), and the McVicar Arm (south).

9. Lake Malawi, 29,500 km²

Lake Malawi. Photo by Noel Peries, via www.maggieinafrica.com

Lake Malawi, also known as Lake Nyasa or Lago Niassa, is the major meromictic lake which has a total surface area of around 11,400 sq mi (29,600 km²). Meromictic lake means that its water layers do not mix. The permanent stratification of the water and the oxic-anoxic boundary relating to oxygen in the water are maintained by moderately thermal gradients and small chemical.

Ancient Lake Malawi has been tipically estimated to be 1-2 million years old which formed by a divergent plate tectonics boundary. However, the recent evidence has been estimated that the basin started to form about 8.6 million years ago and deep-water condition first occurred 4.5 million years ago.

Lake Malawi is famous for the huge swarms of harmless lake flies called Chaoborus edulis. These swarms can be mistaken for plumes of smoke. The larvae are food source for fish, and the adult flies are collected by local people to make a very high protein local delicacy, i.e. kunga cakes.

10. Great Slave Lake, 27,200 km²

Great Slave Lake is the deepest lake in North America at 614 metres, and the second-largest lake in the Northwest Territories of Canada which covers an area of 27,200 km² (10,502 sq mi). It has one ice road known as the Dettah ice road that connects the Northwest Territories capital of Yellowknife to Dettah.

Great Slave Lake is a remnant of the vast glacial Lake McConnell. The lake has a very irregular shoreline. The western shore is forested, but the east shore and northern arm are tundra-like. The lake is partially frozen for around eight months every year.

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