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 South Korean woman looks out at the flood water after a torrential rain storm hit the capital city on July 27, 2011 in Seoul, South Korea. South Korea issued a national crisis warning on as torrential rain caused flooding in parts of the country, killing over 35 with at least ten missing. (Photo by Chung Sung-Jun/Getty Images)

Ryo Minemizu, one of Japan’s emerging stars in the field of marine life photography and the 2017 winner of the Nikkei National Geographic photography prize, captures the beauty and complexity of plankton that drift in our planet’s oceans and other bodies of water in meticulous detail. Here: Batesian mimicry by a Soleichthys fish larva. (Photo by Ryo Minemizu/The Guardian)

People work with cocoa beans in Enchi June 17, 2014. Picture taken June 17, 2014. Ghana emerged as a success story during the 2000s, when war, political instability and a disastrous liberalization brought Ivory Coast's cocoa sector to its knees. Ghana's output more than tripled from 340,000 tons in the 2001/02 season to a record 1,025,000 tons a decade later. Strict controls cemented its reputation as a producer of top quality beans, establishing a brand that fetches a premium. (Photo by Thierry Gouegnon/Reuters)

Daniel J. Wabsey, a 58-year-old war veteran, sits outside his tent at Camp Hope in Las Cruces, New Mexico October 6, 2015. “I've been traveling for 35 or 38 years. Getting inside would take a while to get used to. I just want to be able to eat, sleep and be safe. We all get along and understand in Camp Hope. We've all been there. With common sense you can survive out here”, Wabsey said. Camp Hope describe themselves as an “alternative transitional living project for the homeless”. Around 50 people live at the camp. (Photo by Shannon Stapleton/Reuters)

The expertly colourised shots were brought to life by French bank technician, Frédéric Duriez (51). The images were provided by the Valois collection which belongs to the BDIC. “By colourising these photos, I reduce the time that separates us today from this conflict”, said Frédéric. Here: Car cannon sections in firing position, Auxi-le-Château. (Photo by Frédéric Duriez/BDIC/Mediadrumworld.com)

Ukrainian artist Dariya Marchenko works on a portrait of Russian President Vladimir Putin named “The Face of War” which is made out of 5,000 cartridges brought from the frontline in eastern Ukraine, in Kiev, July 23, 2015. The portrait will be presented along with a novel which will tell personal stories of six people involved in this project including Daria's own story and stories of people who helped her to collect shells from the frontline. Daria Marchenko calls her art approach philosophic symbolism where every element has its hidden meaning. In her works cartridges mean human's life that was brutally ended. (Photo by Gleb Garanich/Reuters)

It looks like an underwater tornado, but a diver was actually stuck in the middle of a huge school of fish. The fish swarmed around Mika Woyda in their thousands as she swam off the coast of Cabo Pulmo, Mexico. Her husband Caine Delacy snapped the breath-taking images of Mika in scenes he revealed he had never witnessed in 20 years of diving. Before entering the water the couple, who live in Boulder, Colorado, had some shots in mind but never imagined what they would capture. Here: photographer Caine Delacy with his wife Mika Woyda. (Photo by Caine Delacy/Mika Woyda/Caters News)