People run along a street as rain caused by tropical storm Alberto, the first named storm of 2024 Atlantic hurricane season, falls, in Monterrey, Mexico. on June 19, 2024. (Photo by Daniel Becerril/Reuters)

A firefighter is seen next to flames while working to extinguish a wildfire burning in Gondomar, northern Portugal on July 29, 2025. Almost 2,000 firefighters battled on July 29, 2025 to contain forest blazes across Portugal that have led to almost the whole country being put on high alert for fires. Ten major fires blazed with two in the north and three in the centre of the country causing most concern. (Photo by Carlos Costa/AFP Photo)

A cyclist rides past a tumulus tomb in Gyeongju, South Korea on November 1, 2025. (Photo by Anthony Wallace/AFP Photo)

England goalkeeper Mary Earps saves a penalty from Jennifer Hermoso of Spain during the FIFA Women's World Cup Australia & New Zealand 2023 Final match between Spain and England at Stadium Australia on August 20, 2023 in Sydney, Australia. (Photo by Charlotte Wilson/Offside/Offside via Getty Images)

Tommy Lindsey holds an enormous maple leaf that he found in Mount Vernon, Wash., October 28, 2013. Lindsey was walking with his family when he picked up the leaf that is more than two feet from stem to tip and more than 21 inches wide. (Photo by Frank Varga/The Skagit Valley Herald)

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.