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.

Jaida Zuniga #5 returns a volley against Northview during a girls volleyball match on grass as part of the newly formed Grass Valley League at Northview High School in West Covina on Thursday, March 4, 2021. South Hills defeated Northview (21-25), 25-13, 25-9, 25-12. (Photo by Keith Birmingham, Pasadena Star-News/SCNG)

A resident pushes their motorbike through flood waters caused by torrential rain in Semarang, central Java, Indonesia on February 23, 2021. (Photo by W.F. Sihardian/NurPhoto/Rex Features/Shutterstock)

A pack of wild smooth-coated otters, nicknamed the “Zouk family”, crosses Penang Road in Singapore on March 3, 2021, the World Wildlife Day. The “Zouks”, a well-known otter family in Singapore, started out from the Istana on Wednesday, and made a “royal” tour of various landmarks in Singapore. (Photo by Chine Nouvelle/SIPA Press/Rex Features/Shutterstock)

Freshmen in Zhengzhou Institute of Aeronautical Industry Management head bottles of mineral water for upright stand during military training on September 17, 2015 in Zhengzhou, Henan Province of China. More than 6,800 freshmen in the school are required to take part in the military training. (Photo by ChinaFotoPress/ChinaFotoPress via Getty Images)

Starlings gather on power lines at dusk, Friday, October 21, 2022, in Overland Park, Kan. (Photo by Charlie Riedel/AP Photo)

People explore the ice covered pier in Port Stanley, Ontario, Canada, on December 27, 2022. The ice formations were created by a large winter storm which hit the region on over the Christmas weekend. Temperatures were expected to moderate across the eastern and midwest US on December 27, after days of freezing weather from "the blizzard of the century" left at least 49 dead and caused Christmas travel chaos. (Photo by Geoff Robins/AFP Photo)