“The power of nature”. Magma, ash and gas erupt from Mount Etna in December 2015, rising to a height of several kilometres. Winner: Nature. (Photo by Giuseppe Mario Famiani/SIPA Contest)

Aerial view of CRH bullet trains setting out ahead of Spring Festival travel rush on January 31, 2018 in Hefei, Anhui Province of China. About 2.98 billion trips will be made during the 40-day Spring Festival travel rush. China will take multiple measures to ensure a smooth Spring Festival travel rush. (Photo by VCG/VCG via Getty Images)

A girl cover her face while riding a motorcycle as haze shrouds a street near Tanjung Siapi Api port in Palembang, on the Indonesian island of Sumatra, September 19, 2015. Indonesia will take 30 days to bring smouldering forest fires under control, the national disaster management agency said on Friday, as smog from the fires pushes pollution in Southeast Asia to record highs. (Photo by Reuters/Beawiharta)

Activists stage a protest outside the Louvre pyramid, calling the museum to cancel its contracts with French oil giant Total and Italian oil company Eni, in Paris, France, December 9, 2015, as the World Climate Change Conference 2015 (COP21) continues at Le Bourget near the French capital. (Photo by Benoit Tessier/Reuters)

Soldiers are reflected in a puddle during a military parade during the celebrations for Romania's National Day in Bucharest December 1, 2014. (Photo by Radu Sigheti/Reuters)

A demonstrator attends a protest against fare hikes for city buses in Rio de Janeiro January 16, 2015. Amid a marked economic downturn and high inflation, bus fares went up in Sao Paulo, Brazil's largest city, from 3 to 3.50 reais, and in Rio, the former capital, from 3.0 to 3.40 reais. (Photo by Mauro Pimentel/Reuters)

The giant mural titled “Under the Hand” by Maclaim Crew is visible on a building facade in Kreuzberg district on June 26, 2014 in Berlin, Germany. Berlin, with its long tradition of counter-culture, has become a mecca for street art of all dimensions and messages. (Photo by Sean Gallup/Getty Images)

A man walks past specially designed wash basins in a public toilet at the Foreigners Street on April 26, 2007 in Chongqing Municipality, China. (Photo by China Photos/Getty Images)