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.

A containment shelter for the damaged fourth reactor (L) and the New Safe Confinement (NSC) structure (R) at the Chernobyl Nuclear Power Plant are seen from Ukraine's abandoned town of Pripyat, Ukraine, April 22, 2016. (Photo by Gleb Garanich/Reuters)

In this photo taken late Thursday, May 7, 2015, a prison guard, left, and seated inmates cast shadows on a wall while waiting for the beginning of a rock concert by Romanian band Pro Musica, inside the Popa Sapca jail in Timisoara, western Romania. (Photo by Adi Piclisan/AP Photo)

A young macaque perches on a pole, observing nearby tourists while eating some seeds in Jigokudani Yaen-koen wild macaque monkey park on February 16, 2015 in Yamanouchi, Nagano, Japan. (Photo by Manuel Romaris/Getty Images)

A young woman poses for a selfie at Red Square which is under preparations for the Victory Parade during sunset in Moscow, Russia, Monday, April 26, 2021. Russia will celebrate celebrate 76 years of the victory in WWII on May 9, 2021. (Photo by Alexander Zemlianichenko/AP Photo)

A Palestinian man sits on a damaged car following Israeli airstrikes on Jabaliya refugee camp, northern Gaza Strip, Thursday, May 20, 2021. Heavy airstrikes pummeled a street in the Jabaliya refugee camp in northern Gaza, destroying ramshackle homes with corrugated metal roofs nearby. The military said it struck two underground launchers in the camp used to fire rockets at Tel Aviv. (Photo by Khalil Hamra/AP Photo)

Turkish National athlete Sahika Ercumen persists in her preparations for the dive along the shores of Karamagara Bay as she will dive to break the 105-meter world record in the variable weight category without fins on the 100th anniversary of the Turkish Republic in Hatay, Turkiye on October 15, 2023. The national athlete is determined to exceed the 105-meter world record currently held by Serbian diver Lena Balta in the variable weight category without fins. (Photo by Sebnem Coskun/Anadolu via Getty Images)

Young Legong dancer portrait, Ubud, Bali on October 25, 2023. While the childrens' parents are out working, in pursuits including farming, fishing and clothes making, their offspring spend the long sunny days making their own fun, and as these pictures show not a minute is wasted. (Photo by David Lazar/Animal News Agency)