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.

An Iraqi army cadet performs “the leap of faith” from a bridge in Baghdad, September 22, 2015. (Photo by Ahmed Saad/Reuters)

Iranian soccer fan wait for the start of the group B match between Iran and Spain at the 2018 soccer World Cup in the Kazan Arena in Kazan, Russia, Wednesday, June 20, 2018. (Photo by Diego Azubel/EPA/EFE)

A contestant prepares at the backstage before the Miss Transqueen India 2018 transgender beauty pageant in Mumbai, India on October 7, 2018. (Photo by Francis Mascarenhas/Reuters)

Hong Kong art gallery director Sarah Greene said that Wolf, known for his work depicting mega-cities, has died Tuesday, April 24, 2019 night at his home. She said he was 64. Wolf won first prize in the World Press Photo competition in 2005 and 2010. Here: Architecture of Density #119, 2009. (Photo by Michael Wolf, courtesy of Flowers Gallery)

Bud Light Hotel Correspondent Leila Mahadin (R) interviews a Playboy Bunny at the 2012 Playboy Party hosted by Bud Light Hotel at Bud Light Hotel on February 3, 2012 in Indianapolis, Indiana. (Photo by Stephen Lovekin/Getty Images for Bud Light Hotel)

Young African lion Asali (R) jumps for a bungee-ball toy as her father Jambo or “Bruiser” looks on at the opening of a savannah-themed makeover of the lion enclosure at Taronga Zoo August 29, 2006 in Sydney, Australia. The renovation includes sandstone rock features, a wading pool, and red ochre crushed granite substrate in a move to make the enclosure more closely resemble the natural habitat of the African savannah. (Photo by Ian Waldie/Getty Images)

Fashion designer Hans M. Bachmayer (L), Susanne Wiebe (2R) and Rosanna Davison (R) attend the Susanne Wiebe Fashion Show on August 12, 2011 in Munich, Germany. (Photo by Johannes Simon/Getty Images)