A man pushes her daughter on a cart as they shop at a market in Seoul, South Korea, July 26, 2016. (Photo by Kim Hong-Ji/Reuters)

A man washes his horse as a woman bathes her son at concrete water pens under a flyover in a slum area in Kolkata, India October 21, 2016. (Photo by Rupak De Chowdhuri/Reuters)

A Kashmiri villager shouts freedom slogans during the funeral procession of Asadullaha Kumar in Mandhaal village, some 70 Kilometers south of Srinagar, Indian controlled Kashmir, Saturday, December 3, 2016. Hundreds of angry villagers blocked the Srinagar-Jammu highway for hours alleging Kumar was tortured and then shot by Indian forces while he was performing his duty as a security guard at a government fishery. Police officers denied the allegation and said he was killed in cross-firing during an overnight counter-insurgency operation in south Kashmir. (Photo by Dar Yasin/AP Photo)

Syrian government troops patrol the newly captured al- Sakhour neighbourhood in the eastern part of the northern city of Aleppo on December 7, 2016 Rebels in Aleppo called for a five- day truce and the evacuation of civilians Wednesday after losing more than three quarters of their territory including the Old City to a Syrian army offensive. (Photo by George Ourfalian/AFP Photo)

A dirty thunderstorm occurs over Mount Sakurajima as the volcano erupts violently at 12:03 am on July 26, 2016 in Tarumizu, Kagoshima, Japan. The eruption occurred at the mountain's Showa crater. This is the first time that the active volcano in southern Kyushu has spewed out a smokestack that high since an eruption on August 18, 2013, according to the Kagoshima Meteorological Office. (Photo by The Asahi Shimbun via Getty Images)

A new book published by the UK Natural History Museum showcases some of the most memorable underwater photographs taken over the last few decades in its annual wildlife photographer of the year competition. Here: Giant gathering by Tony Wu. “The first indication that something extraordinary was going on were the blows, huge numbers of them – the exhalations of huge numbers of whales. Entering the water, the photographer witnessed an extraordinary scene”. (Photo by Tony Wu/Unforgettable Underwater Photography/NHM)

Model and current Victoria's Secret Angel Elsa Hosk is seen wearing Jacob and Co jewelry while out and about in New York City on April 26, 2018. (Photo by Peter Parker/Splash News and Pictures)

Brain-on-a-chip. Dazzling in green and magenta this image shows the nerve fibres (in green) produced by neural stem cells (in magenta) as they grow on a synthetic gel. Captured by a technique known as confocal microscopy, the image is part of research shedding light on how tinkering with the environment can affect the way in which nerve fibres grow. (Photo by Collin Edington and Iris Lee/Massachusetts Institute of Technology/Wellcome Images)