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.

ESA astronaut Paolo Nespoli looks on after landing back on Earth from their Soyuz TMA-20 spacecraft on May 24, 2011 in Zhezkazgan, Kazakhstan. The mission of the Soyuz TMA-20 was launched last December to the International Space Station with the flight engineers Catherine Coleman from the United States, Russian cosmonaut Dmitry Kondratyev and Italian astronaut Paolo Nespoli. The next expedition is expected to launch this June. (Photo by Stephane Corvaja/ESA via Getty Images)

Russian-born artist Vlad Korneev poses for a picture in his museum called “Designpanoptikum, Museum For Extraordinary Objects” on November 4, 2010 in Berlin, Germany. The museum displays objects whose outward appearance was determined by function rather than form, he says, and are the result of a collection he started while accumulating props for his photographic works. (Photo by Sean Gallup/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)

A Ukrainian serviceman who fought in Debaltseve is seen near Artemivsk February 19, 2015. Fighting raged in eastern Ukraine on Thursday despite European efforts to resurrect a still-born ceasefire, a day after pro-Russian separatists who spurned the truce forced thousands of government troops out of a strategic town. (Photo by Gleb Garanich/Reuters)

Members of Japan's idol group “Virtual Currency Girls” wearing cryptocurrency-themed masks perform in their debut stage in Tokyo, Japan, January 12, 2018. Japanese female idols have teamed up to form the ‘Virtual Currency Girls’ group to promote the knowledge of cryptocurrencies through entertainment. Each of its 8 members represents a cryptocurrency: bitcoin cash, bitcoin, ether, neo, nem, ripple, mona, and cardano. (Photo by Kim Kyung-Hoon/Reuters)

An actor dressed as a zombie performs during a drive-in haunted house show by Kowagarasetai (Scare Squad), for people inside a car in order to maintain social distancing amid the spread of the coronavirus disease (COVID-19), at a garage in Tokyo, Japan on July 3, 2020. A Japanese performance group is starting a run of drive-in horror shows for people who are scared of catching the coronavirus but still want to get close-up frights from ghouls and zombies. Audience members will drive into a garage in Tokyo, one car at a time, and listen to a murder story and sound effects blared out of speakers, as actors dressed as monsters bang on the side of the vehicle and spray fake blood over the windows. (Photo by Issei Kato/Reuters)

Japan's On-Art Corp's eight metre tall dinosaur-shaped mechanical suit robot “TRX03” performs during its unveiling in Tokyo, Japan November 10, 2016. Stomping and roaring dinosaurs took to the stage in Tokyo on Thursday as part of a presentation for a proposed entertainment park where visitors will be able to see the realistic replicas first-hand. Japanese firm ON-ART Corp. unveiled man-operated robotic models of raptors, an allosaurus and a tyrannosaurus rex, in a performance at a hotel hall. (Photo by Toru Hanai/Reuters)