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.

Female Chimpanzee “Fifi” eats carrots as she sits in her enclosure at Taronga Zoo on her 60th birthday May 21, 2007 in Sydney, Australia. Fifi is the oldest of the Zoo's chimp population, which consists of 19 individuals. (Photo by Ian Waldie/Getty Images)

Ford displays the drive train of the F150 Raptor SVT truck during the media preview of the Chicago Auto Show at McCormick Place on February 8, 2012 in Chicago, Illinois. The show, which is the largest and oldest auto show in the country, opens to the public on February 10. (Photo by Scott Olson/Getty Images)

Students dance in the hallway during a break at Moscow State Academy of Choreography in Moscow, Russia 03 March 2016. Moscow State Academy of Choreography is the oldest institution in Moscow which teaches Ballet arts not only Russian citizens, but also representatives from more than 20 countries. (Photo by Yuri Kochetkov/EPA)

Lioness and hyena posture to one another, in Masai Mara, Kenya, August 2015. A photographer captured one of the oldest rivalries in the animal kingdom as a pair of lions went head to head with a pack of hungry hyenas. (Photo by Ingo Gerlach/Barcroft Images)

A woman looks at some of the 60 plane trees wrapped in a pink-and-white polka-dot design developed especially for Melbourne by Japanese contemporary artist Yayoi Kusama titled “Ascension of Polka Dots on the Trees”, in Melbourne on November 27, 2024. The National Gallery of Victoria’s (NGV) world-premiere blockbuster exhibition Yayoi Kusama will be on display from 15 December 2024 to 21 April 2025. (Photo by William West/AFP Photo)

Migle Politike (left) with son Aaron and friend Goda Zubkaityte on Wednesday, June 11, 2025 stop to look at the Singing Ringing Tree, a musical sculpture designed to look like a windswept tree, at Crown Point overlooking Burnley, Lancashire, UK. The wind-powered musical sculpture emits a low, tuneful song when the wind blows. (Photo by Martin Rickett/PA Wire)