A Polisario fighter sits on a rock at a forward base on the outskirts of Tifariti, Western Sahara, September 9, 2016. At a rocky outpost in Western Sahara, a new generation of soldiers who have never known war are mobilising as tensions resurface in one of Africa's oldest disputes after a quarter century of uneasy peace. (Photo by Zohra Bensemra/Reuters)

A Santa Claus puppet holding a Christmas tree is pictured against the sun in Berlin November 23, 2014. (Photo by Hannibal Hanschke/Reuters)

Two men using an electric power saw to fell a tree circa 1940's. (Photo by Keystone View/FPG/Getty Images)

Bad Christmas gift makes the pretty girl look disappointed in x-mas time under the christmas tree. (Photo by pixelrain/Rex Features/Shutterstock)

A woman in Kimono poses for photos in front of mimosa and cherry blossom trees in Tokyo on March 8, 2024. (Photo by Yuichi Yamazaki/AFP Photo)

A car drives between trees in a small park in Frankfurt, Germany, Monday, April 8, 2024. (Photo by Michael Probst/AP Photo)

Lioness and hyena posture to one another, in Masai Mara, Kenya, August 2015. A photographer captured one of the oldest rivalries in the animal kingdom as a pair of lions went head to head with a pack of hungry hyenas. (Photo by Ingo Gerlach/Barcroft 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.