In this March 22, 1975 file photo, a refugee clutches a baby as a government helicopter gunship carries them away near Tuy Hoa, Vietnam, 235 miles northeast of Saigon. They were among thousands fleeing from Communist advances. AP Photographer Nick Ut will be retiring from the AP in March 2017 after 51 years of taking photographs from the front lines of the Vietnam War to the red carpets of Hollywood. (Photo by Nick Ut/AP Photo)

In this April 4, 2017 photo, Zoologist Martha Llanes caresses baby chimpanzee Anuma II, left, while Ada hangs on to her leg, at Llanes' apartment in Havana, Cuba. She has forgiven them every transgression. It's hard to stay angry at a baby chimpanzee when it clambers up your leg and into your arms and plants a kiss on your cheek in a plea for forgiveness. (Photo by Ramon Espinosa/AP Photo)

Two ruddy shelducks fly under a double rainbow in Odisha, India in July 2022. These birds are ruddy shelduck, known locally as the Brahminy duck. They have a wingspan of between 43 and 53 inches and stand at a maximum of 28 inches tall. (Photo by Suman Das/Media Drum Images)

Woman and man playing domination games in bed. (Photo by NDAB Creativity/Rex Features/Shutterstock)

An areal view of the lake in the form of a heart in Rodgau, near Frankfurt, Germany, Friday, May 24, 2024. (Photo by Michael Probst/AP Photo)

Performers take part in a procession as part of the Samhuinn Fire Festival on October 31, 2024 in Edinburgh, Scotland. The Samhuinn Fire Festival is a modern take on an ancient Celtic festival, marking the transition between summer and winter with fire-dancing, drums, acrobatics, and theatre performances. (Photo by Jeff J. Mitchell/Getty 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.

Participants of the “Still Standing for Culture” action of the cultural sector rally in Les Marolles neighborhood of Brussels, Belgium, 13 March 2021. Workers of the cultural sector along with second-hand dealers of the Jeu de Balle place gathered in Les Marolles to denounce the lack of financial support and call for solutions to the impact of the coronavirus crisis on culture professionals and the sector as a whole one year after the Covid-19 pandemic lockdowns started. (Photo by Stephanie Lecocq/EPA/EFE)