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.

In this photograph taken on October 27, 2017 an Afghan woman collects saffron flowers after picking them in a field on the outskirt of Herat For years, Afghanistan has tried to give farmers alternatives such as fruit crops and saffron to wean them away from poppy farming – the lifeblood of the Taliban insurgency. International donors have splurged billions of dollars on counter- narcotics efforts in Afghanistan over the past decade, including efforts to encourage farmers to switch to other cash crops such as saffron. But those efforts have shown little results. (Photo by Hoshang Hashimi/AFP Photo)

A Hawaiian cleaner wrasse provides its cleaning services to a yellowfin goatfish in a reef community off the Big Island in Hawaii. Cleaner species help rid their hosts of ectoparasites, dead tissue, bacteria and fungi. Studies have shown cleaning to play a vital role in keeping many reef ecosystems healthy. (Photo by Marty Snyderman/Caters News Agency)

Members of the U.S. Army's Golden Knights parachute team perform during the Bethpage Air Show as part of a Memorial Day event at Jones Beach on Long Island, New York, U.S., May 25, 2019. (Photo by Johnny Milano/Reuters)

Aerial photo taken on April 20, 2018 shows the view of advection fog above Qingdao, a coastal city in east China' s Shandong Province. (Photo by Lu Hui/Xinhua News Agency/Eyevine)

A roadside vendor selling apples is seen through a plastic sheet that he uses to cover himself from rain, in Srinagar, Indian state of Jammu and Kashmir on November 14, 2018. (Photo by Danish Ismail/Reuters)

Convicted murderer Hector Alvarado Mazariegos, right, drops to the ground as he is hit by bullets of a Guatemala firing squad in the public cemetery at Mazatenango, June 28, 1975. His companion, Rocael Ortiz, met the same fate a few seconds later. Both were convicted of murder. (Photo by AP Photo/Anzueto)

Van cats, relatively large, have a chalky white coat, sometimes with ruddy coloration on the head and hindquarters, and have blue or amber eyes or have heterochromia, are seen at “Cat Villa”, established to protect the cats in Van, Turkey on January 20, 2021. Internationally valid “health certificate” is prepared for Van cats, visited by local and foreign tourists, within a project to protect their generations and increasing their numbers. Health certificates with information such as name, breed, gender, eye color, date of birth, tail feature, color, hearing status and identity are given to people who want to adopt cats. (Photo by Mesut Varol/Anadolu Agency via Getty Images)