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 brushtail possum whose ears and legs have been burnt from recent bushfires sits in a cage before being transported to a wildlife hospital, in Batemans Bay, South of Sydney, Australia, 14 January 2020. (Photo by Steven Saphore/EPA/EFE)

Steven Busulwa, an animal keeper, runs away from a charging rhino at the Uganda Wildlife Conservation Education Center (UWEC) amid the lockdown as part of the measures taken to prevent the spread of the coronavirus disease (COVID-19), within Wakiso district, in Entebbe, Uganda on April 20, 2020. (Photo by Abubaker Lubowa/Reuters)

A zoo keeper holds a month old striped Hyena cub called Hachi at the Bali zoo in Giayar, Bali Indonesia on Saturday, February 6, 2021. (Photo by Firdia Lisnawati/AP Photo)

A man feeds langur monkeys during a lockdown amid the Covid-19 coronavirus pandemic in Pushkar on April 28, 2021. (Photo by Himanshu Sharma/AFP Photo)

Police officers detain an activist to prevent her from marching in a pride parade, which was banned by local authorities, in central Istanbul, Turkey on June 26, 2022. (Photo by Umit Bektas/Reuters)

The Godson family had faced eviction over neighbours' complaints about the birds squawking and swearing. Now, after the family were targeted in a drive-by smoke-bomb attack over the birds they have upped and moved 200 miles from Hemel Hempstead, Herts, to Minehead, Somerset. And their pets join in their new idyllic coastal life – by walking along the beach with them on May 9, 2023. (Photo by Neil Hope/The Sun)

A killdeer (Charadrius vociferus) chick on sand dunes in Pacific Grove, California, US on June 21, 2023. The killdeer gets its name from its shrill, loud call. (Photo by Rory Merry/ZUMA Press Wire/Rex Features/Shutterstock)