Lake Baikal is the world's oldest lake, at 25 million years (possibly older), and deepest, averaging 744.4 metres (2,442 ft).

Located in the south of the Russian region of Siberia, between Irkutsk Oblast to the northwest and the Buryat Republic to the southeast, it is the most voluminous freshwater lake in the world, containing roughly 20% of the world's unfrozen surface fresh water.

A seven week old Daschund cross puppy waits to be re-homed at the Cheshire Dogs Home on January 4, 2010 in Warrington, England. (Photo by Christopher Furlong/Getty Images)

The New World porcupine, family Erethizontidae, 1280 Gram born at 11 April 2015 Inventory in Zoo. Counting trade Fairs Weighing the Zoo is at 7 May 2015 too the 108 Birthday Zoo Hagenbeck Hamburg, Germany. (Photo by Imago/ZUMA Wire)

Monkeys sit along a street during a snowfall in Ayubia, some 75 km north of Islamabad, Pakistan on January 7, 2020. (Photo by Aamir Qureshi/AFP Photo)

Migrant children run away from clashes with Mexican National Guards after their group crossed the Suchiate River on foot from Guatemala to Mexico, on the riverbank near Ciudad Hidalgo, Mexico, Monday, January 20, 2020. More than a thousand Central American migrants hoping to reach the United States marooned in Guatemala are walking en masse across a river leading to Mexico in an attempt to convince authorities there to allow them passage through the country. (Photo by Santiago Billy/AP Photo)

An ostrich is seen at Woburn Safari park before its opening as coronavirus disease (COVID-19) restrictions begin to ease, in Woburn, Britain on April 11, 2021. (Photo by Andrew Boyers/Reuters)

Giant panda Shuixiu's two babies are pictured at their room in Shenshuping base of China Conservation and Research Center for the Giant Panda on November 3, 2021 in Aba Tibetan and Qiang Autonomous Prefecture, Sichuan Province of China. (Photo by An Yuan/China News Service via Getty Images)

People walk in the rain in Hyderabad, India, Saturday, November 20, 2021. More than a dozen people have died and dozens are reported missing in the southern Indian state of Andhra Pradesh after days of heavy rains, authorities said. (Photo by Mahesh Kumar A./AP Photo)