Two women jump from a platform over the water at La Concha beach during a hot summer day in the basque city of San Sebastian, northern Spain, Friday, August 3, 2018. Hot air from Africa is bringing a heat wave to Europe, prompting health warnings about Sahara Desert dust and exceptionally high temperatures that could peak at 47 degrees Celsius (117 Fahrenheit) in Spain and Portugal. (Photo by Alvaro Barrientos/AP Photo)

A toque macaque is eating flowers in the water at the pilgrimage site in Polonnaruwa, Sri Lanka, on January 13, 2024. The toque macaque (Macaca sinica), a reddish-brown-colored Old World monkey, is endemic to Sri Lanka, where it is known as the rilewa or rilawa. It is named for the whorl of hair at the crown of its head, which resembles a brimless toque cap. (Photo by Thilina Kaluthotage/NurPhoto/Rex Features/Shutterstock)

A common gallinule runs across the water to escape a nearby alligator at Green Cay Nature Center in Boynton Beach, Florida on September 4, 2025. Unlike most waterbirds, gallinules have long toes that allow them to walk on floating vegetation. The species is known for its loud, cackling calls that often echo through wetlands. (Photo by Ronen Tivony/NurPhoto/Rex Features/Shutterstock)

A milkman crosses through floodwater at Chak Ali Sher village in Wazirabad district on August 28, 2025, after government issued a flood alert for riverside areas of Punjab province. Water has gushed into the eastern province, Pakistan's breadbasket and home to about half of its 255 million people, with three transboundary rivers swelling beyond their banks. The latest monsoon downpour has killed at least 13 people, according to the National Disaster Management Authority. (Photo by Aamir Qureshi/AFP Photo)

A young Ukrainian woman wears an ear of grain braid during a traditional Ukrainian celebration of Kupalo Night, in Warsaw, Poland, on Saturday, June 22, 2024. Ukrainians in Warsaw jumped over a bonfire and floated braids to honor the vital powers of water and fire on the Vistula River bank Saturday night, as they celebrated their solstice tradition of Ivan Kupalo Night away from war-torn home. (Photo by Czarek Sokolowski/AP Photo)

A South Korean woman looks out at the flood water after a torrential rain storm hit the capital city on July 27, 2011 in Seoul, South Korea. South Korea issued a national crisis warning on as torrential rain caused flooding in parts of the country, killing over 35 with at least ten missing. (Photo by Chung Sung-Jun/Getty Images)

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.