Models painted in camouflage colours to blend in with the background pose for Chinese artist Liu Bolin's artwork “Dongji”, or Winter Solstice, on the second day after China's capital Beijing issued its second ever “red alert” for air pollution, in Beijing, China, December 20, 2015. In this artwork, Liu wants to express his concerns about China and its people, including air pollution problem, Liu told Reuters. (Photo by Kim Kyung-Hoon/Reuters)

A women attends a class at a driving school in Kabul August 17, 2014. Kabul is one of the world's fastest growing cities and its streets are increasingly blocked by cars and buses. In the city's private driving schools, students pay a $60 fee for a 45-day course, which includes oral and practical driving tests at the country's Traffic Department. Some of the women who have signed up say learning to drive is a way to escape unwanted gazes and physical harassment on the cramped, crowded minibuses that are often the only method of urban public transport. (Photo by Mohammad Ismail/Reuters)

A man salts a downtown sidewalk in Washington, Thursday, March 5, 2015, as snow begins to fall. The U.S. federal government said its offices in the Washington area will be closed Thursday because of a new round of winter weather expected in the region. The Office of Personnel Management said non-emergency personnel in and around Washington were granted excused absences for the day. Emergency employees and telework-ready employees were expected to work. (AP Photo/Andrew Harnik)

A Kenyan soldier takes cover as shots are fired in front of Garissa University in Garissa town, located near the border with Somalia, some 370km northeast of the capital Nairobi, Kenya, 02 April 2015. At least 15 people have been killed and some 60 were injured in an attack carried out by Somalia's Islamist militant group al-Shabab, according to local media reports. (Photo by Dai Kurokawa/EPA)

A handout picture provided by the press service of MORTON Group of Companies, show the balloon of Russian adventurer Fedor Konyukhov in the sky during his solo round-the-world balloon flight just after taking off from a spot near Northam, 96 kilometres north-east of Perth in Western Australia, 12 July 2016. Fedor Konyukhov took off from Northam on 12 July 2016 in attempt to beat the record of 13 days of American aviator Steve Fossett. (Photo by EPA/Morton Press Service)

Nepalese Hindu women pray to worship Lord Shiva during the first day of the Sarwan Brata festival, the month of fasting, at the premises of Pashupati Temple in Kathmandu, Nepal, 18 July 2016. Thousands of married and single Nepalese Hindu women will gather in temples for each Monday of the Sawan month (spanning from 16 July to 16 August) to pray for a long and prosperous life of their husbands or for a chance to find a good one. (Photo by Narendra Shrestha/EPA)

A cat tries to find dry ground around an apartment complex in Houston after Hurricane Harvey hit on Aug. 30. Harvey made landfall in South Texas on August 25, leading to days of downpours that dumped more than 50 inches of rain. Harvey damaged or destroyed about 200,000 homes as the storm system flooded much of Houston and smaller coastal communities. (Photo by Scott Olson/Getty Images)

People and Nature category winner: Why did the sloth cross the road? by Andrew Whitworth (Osa Conservation and University of Glasgow), taken in Osa Peninsula, Costa Rica. “I was driving out from the Osa Peninsula, located on the southern Pacific coast of Costa Rica on a dark, stormy day. This female three-toed sloth (Bradypus variegatus) had luckily just about made it across the road, and the drivers of the Toyota on this occasion had spotted her in good time”. (Photo by Andrew Whitworth/2019 British Ecological Society Photography Competition)