People hold up face masks with William Shakespeare's portrait during celebrations to mark the 400th anniversary of the playwright's death in the city of his birth, Stratford-Upon-Avon, Britain, April 23, 2016. (Photo by Dylan Martinez/Reuters)

Members of the public interact with “Impulse” by Lateral O ce and CS Design during Lumiere London festival of light 2018 on January 18, 2018 in London, England. Lumiere London is a four night long light festival spanning the British capital with more than 50 artworks by UK and international aritsts. (Photo by Dan Kitwood/Getty Images)

A man dressed as Santa Claus lights a Christmas tree on City Hall square in Copenhagen, Denmark, on November 27, 2022. (Photo by Sergei Gapon/Anadolu Agency via Getty Images)

Commuters make their way through a flooded street after a heavy rain shower in Lahore on July 14, 2022. (Photo by Arif Ali/AFP Photo)

Uruguay's Julia Paternain reacts after crossing the finish line to win the bronze medal in the women's marathon at the World Athletics Championships in Tokyo, Sunday, September 14, 2025. (Photo by Matthias Schrader/AP Photo)

A model takes selfie with mobile phone as she presents a creation from the Dolce & Gabbana Spring/Summer 2016 collection during Milan Fashion Week in Italy, September 27, 2015. (Photo by Stefano Rellandini/Reuters)

Russian soldiers from 34th motorized infantry mountain brigade, 58th Army, prepare to evacuate a fellow soldier acting as an injured person during a drill at the Darial range outside Russia's city of Vladikavkaz, July 28, 2010. (Photo by Kazbek Basayev/Reuters)

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.