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.

Spectators watch Austria's Stefan Kraft in action during the Viessmann FIS Ski Jumping World Cup Willingen on January 31, 2021 in Willingen, Germany. (Photo by Wolfgang Rattay/Reuters)

Iranian bodybuilder Sharareh Nobahari, 30, assists her fitness trainees at a gym in Tehran, Iran on September 20, 2019. (Photo by Nazanin Tabatabaee/Reuters)

MY Raven, a former steamer now converted to diesel, cruises across Ullswater from Glenridding to Pooley Bridge in Cumbria, UK on October 25, 2024. (Photo by Andrew McCaren/London News Pictures)

A woman jumps with balloons while she poses for a picture at a park in Kiev, Ukraine May 6, 2018. (Photo by Valentyn Ogirenko/Reuters)

A vintage American car drives down a road as a crab tries cross the road in Giron, Cuba, Saturday, April 9, 2022. The yearly migration causes concern to drivers that try to swerve in a futile attempt not to kill the crustaceans and are a nuisance to residents but the sight of their travels across the road is a wonder for tourists and anyone interested in the phenomenon. (Photo by Ramon Espinosa/AP Photo)

Commuters make their way through a flooded street after a heavy rain shower in Lahore on July 14, 2022. (Photo by Arif Ali/AFP Photo)

A man stands in front of a poster created by artist Tomoko Konoike, one of 20 posters officially selected for the Tokyo Olympics and Paralympics, at the Museum of Contemporary Art Tokyo Monday, January 6, 2020. The official posters are out for this year's Tokyo Olympics and Paralympics. The 20 posters have been created by 19 artists in fields ranging from painting, graphic design, and photography. Calligraphy and Japanese manga are also represented. (Photo by Jae C. Hong/AP Photo)