China's President Xi Jinping's wife Peng Liyuan, right, and French President Emmanuel Macron's wife Brigitte Macron pose in front of the clock as they visit the Orsay Museum, Monday, May 6, 2024 in Paris. (Photo by Aurelien Morissard/AP Photo)

Icelandic horses play on a meadow in Wehrheim near Frankfurt, Germany, as the sun rises on Tuesday, May 28, 2024. (Photo by Michael Probst/AP Photo)

Participants take part in the 14th annual “No Trousers Tube Ride” event on the London Underground on January 12, 2025. The event, staged by Improv Everywhere, takes place every January in New York City and has since expanded internationally. What began as a small prank with just seven participants has grown into a global celebration of silliness, with dozens of cities, including London, joining in each year. (Photo by Guy Bell/Alamy Live News)

Goodwood racegoers run for cover from a sudden rainstorm on Ladies Day, the third day of the horseracing festival at Goodwood Racecourse on July 31, 2025 in Chichester, England. (Photo by The Times)

The moon rises on the behind the “Torchbearer” statue in Hannover, Germany, Wednesday, November 5, 2025. (Photo by Julian Stratenschulte/dpa via AP Photo)

Roxy, a Red Labradoodle, Jaku, a Black and Tan Lurcher, Kobe, a White German Shepherd, Rocky, a Black and Tan German Shepherd, and Busy, an English Springer Spaniel Cross, queue outside an Aldi store in Hinckley, Leicestershire, UK on Monday, December 1, 2025. (Phoot by Lucy Ray/PA Media Assignments)

Competitors take part in the annual Mud Madness event at Foymore Lodge on April 22, 2018 in Portadown, Northern Ireland. The adult version of the event includes two laps of an 8km course through 25 obstacles while the kids event is run over 2kms. The race is in it's eleventh year and is sponsored by McVities Jaffa Cakes and event charity partner Marie Curie together with other numerous charities and fundraising groups. (Photo by Charles McQuillan/Getty Images)

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.