Fighters Holly “The Lotus” Mei (L) and Teri “Feisty Fists” London train for the upcoming 'Lingerie Fighting Championships 22: Costume Brawl I' at DXG Self Defense on October 25, 2016 in Las Vegas, Nevada. The event is scheduled to feature eight bouts at 4 Bears Casino & Lodge on October 29, 2016 in New Town, North Dakota. (Photo by Ethan Miller/Getty Images)

Almost two years old male baby orang-utan Dalai looks on in the zoo in Dresden, Germany, 30 March 2017. Dalai was born to mother Daisy in June 2016. (Photo by Filip Singer/EPA)

A church made entirely from ice is seen during the night at Balea Lac resort in the Fagaras mountains January 29, 2015. (Photo by Radu Sigheti/Reuters)

A white yak sits on the lakeside of Namtso on May 19, 2024 in Lhasa, Xizang Autonomous Region of China. As temperature rises and ice melts, Lake Namtso is entering its tourism season. An event celebrating the melting of frozen water of Lake Namtso is held on May 19. (Photo by Jin Wei/VCG via Getty Images)

On the morning of the October 4, 2025, the second day of the Chuseok holiday, a lenticular cloud resembling an unidentified flying object (UFO) appeared in the northeastern sky as seen from the Healing Forest in Hogun-dong, Seogwipo-si, Jeju-do, creating a spectacular sight. (Photo by Newsis)

Folk dancers from Chile participate in a folk dance festival in Bitola, North Macedonia on July 26, 2023. (Photo by Ognen Teofilovski/Reuters)

People push a stretcher carrying an injured victim after a mosque blast inside the police headquarters, at a hospital in Peshawar on January 30, 2023. A blast at a mosque inside a police headquarters in Pakistan on January 30 killed at least 25 worshippers and wounded 120 more, officials said. (Photo by Zafar Iqbal/AFP Photo)

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.