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.

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)

Mother and son in disguise attend a Halloween celebration at Taipei Children's Amusement Park in Taipei, Taiwan, Sunday, October 29, 2023. (Photo by Chiang Ying-ying/AP Photo)

Battersea Power Station Ice Rink in London, United Kingdom on November 13, 2022. Running until 8th Jan. 2023, a large outdoor ice-rink outside the power station and next to the riverside brings in festive Christmas fun with vivid illumination. (Photo by Guy Corbishley/Alamy Live News)

A fan of Colombia cheers prior to a qualifying soccer match between for the FIFA World Cup Qatar 2022 Colombia and Chile in Barranquilla, Colombia, Friday, September 10, 2021. (Photo by Fernando Vergara/AP Photo)

Police officers block a road as lava rises following the eruption of a volcano on the Island of La Palma, in Tacande, Spain on September 22, 2021. (Photo by Borja Suarez/Reuters)

Performers in costume wait to take part in the carnival on the main Parade day of the Notting Hill Carnival in west London on August 29, 2022. London's Notting Hill carnival celebrates Caribbean culture, at a carnival considered the largest street demonstration in Europe. (Photo by Susannah Ireland/AFP Photo)

Greece competes in the final of the women's team free artistic swimming event during the World Aquatics Championships in Fukuoka on July 21, 2023. (Photo by François-Xavier Marit/AFP Photo)