A boy and a woman run across a railway track as a train approaches in Chengdu, Sichuan province, China, October 8, 2015. Many residents disregard sign prohibiting this kind of illegal crossing and choose to do so to save time, local media reported. (Photo by Hao Fei/Reuters/Western China Metropolis Daily)

Planes land in fog at Heathrow Airport, west London, as heavy fog covers a many parts of the south east, on April 1, 2014. (Photo by Steve Parsons/PA Wire)

Children react after what activists said was shelling by forces loyal to Syria's President Bashar al-Assad near the Syrian Arab Red Crescent center in the Douma neighborhood of Damascus May 6, 2015. (Photo by Bassam Khabieh/Reuters)

Vocalist Laila Skovmand, a musician with Danish company Between Music, plays underwater in a tank during a rehearsal ahead of their UK premiere concert Aquasonic at the Tramway in Glasgow on Ocrober 25, 2017. (Photo by Robert Perry/PA Images)

A woman takes pictures as Britain driver Lewis Hamilton steers his Mercedes during the third free practice at the Monaco racetrack, in Monaco, Saturday, May 26, 2018. The Formula one race will be held on Sunday. (Photo by Luca Bruno/AP Photo)

A picture taken on March 16, 2017 shows women dressed up as mermaids posing by a pool at a mermaid training school in Moscow. Russian women who have dreamt of becoming a mermaid since their youngest years, start turning their fantasies into reality with a new type of fitness – mermaid swimming. (Photo by Natalia Kolesnikova/AFP Photo)

Women look on as Sauber's German driver Pascal Wehrlein steers his car during the second practice session at the Monaco street circuit on May 25, 2017 in Monaco, three days ahead of the Monaco Formula 1 Grand Prix. (Photo by Andrej Isakovic/AFP Photo)

A sun bear is offered chocolate by a visitor in its enclosure at a zoo in Bandung on January 18, 2017. Animal rights activists on January 18 demanded the closure of an Indonesian zoo after skeletal sun bears were pictured begging for food from visitors and eating their own dung. (Photo by Timur Matahari/AFP Photo)