A man stands in front of a poster created by artist Tomoko Konoike, one of 20 posters officially selected for the Tokyo Olympics and Paralympics, at the Museum of Contemporary Art Tokyo Monday, January 6, 2020. The official posters are out for this year's Tokyo Olympics and Paralympics. The 20 posters have been created by 19 artists in fields ranging from painting, graphic design, and photography. Calligraphy and Japanese manga are also represented. (Photo by Jae C. Hong/AP Photo)

A gallery assistant poses for a photograph with an artwork entitled “John Perreault, 1972” by US artist Alice Neel during a press preview of “Alice Neel: Hot Off The Griddle” at the Barbican Art Gallery in London on February 15, 2023. (Photo by Justin Tallis/AFP Photo)

A rainbow appears as people enjoy a warm afternoon on a tour boat at Niagara Falls in Ontario, Canada on October 21, 2024. (Photo by Mert Alper Dervis/Anadolu via Getty Images)

The waning moon is setting over the mountain “Les Cornettes de Bise” located at the border of the Haute-Savoie and the Valais canton of Switzerland in the Chablais Alps, photographed from Glutieres, January 7, 2015. (Photo by Anthony Anex/EPA)

In this July 29, 2021 file photo, the pillars of the massive Rosario-Victoria Bridge are exposed during a drought affecting the Parana River near Rosario, Argentina. At the port city of Santa Fe the river registered a level of 22 centimeters, the lowest in 50 years. (Photo by Victor Caivano/AP Photo/File)

A South Korea university student gets her head shaved during a protest against Japan's decision to release contaminated water from its crippled Fukushima nuclear plant into the sea, in front of the Japanese embassy, in Seoul, South Korea, April 20, 2021. (Photo by Kim Hong-ji/Reuters)

Spanish flamenco dancer Salome Ramirez performs in the show “Authentic Flamenco”, the show of the Teatro Real in Madrid, at the Sao Pedro theater in Sao Paulo, Brazil, 14 December 2022. After a successful tour in the United States and India, the show has arrived in the country of samba and carnivals, this time by the dancer Eduardo Guerrero and his work “Faro”. (Photo by Isaac Fontana/EPA/EFE/Rex Features/Shutterstock)

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.