People walk during a polluted day in Shenyang, Liaoning province, March 31, 2016. (Photo by Reuters/Stringer)

An Embraer E-190 E2 aircraft featuring a spray painted tiger's face on the nose of the aircraft is displayed during a media preview of the Singapore Airshow February 4, 2018. (Photo by Edgar Su/Reuters)

A man selling bags of water is seen at a taxi parking bay lined with campaign posters in the district of Lingwala in Kinshasa on December 18, 2018. Democratic Republic of Congo goes to the polls on December 23, 2018 in elections which could see the country emerge from 17 years of conflict-ridden rule under controversial President Joseph Kabila. (Photo by John Wessels/AFP Photo)

A Mongolian Bloody Mary, made with pickled sheep eyeballs and tomato juice, is displayed at the Disgusting Food Museum in Malmo, Sweden November 1, 2018. (Photo by Mikael Nilsson/Reuters)

Icicles are seen on a handrail along the coast at Donggang business district in Dalian, Liaoning province, China on December 27, 2018. (Photo by Reuters/China Stringer Network)

Australian performers illuminated with real clocks titled “The Time Minder” attend a media preview of the Night Festival in Singapore on August 23, 2017. Singapore's arts and heritage district will be transformed into Singapore largest outdoor performing arts festival to celebrate its 10th year edition Night Festival from August 24 to 26. (Photo by Roslan Rahman/AFP Photo)

A herd of wildebeest cross the skyline against the fading light in Masai Mara, Kenya, 25 August 2017. Stunning sunset photos silhouette Africa’s wildlife against streaks of orange and red sky. In August, German photographer Ingo Gerlach was on safari in the Masai Mara when he convinced his safari guide to stop and take in the sunset. The wildlife photographer was rewarded with his patience by an eye-catching sunset, which cast Africa’s wildlife into dark shadows against the vibrant skies. (Photo by Ingo Gerlach/Barcroft Images)

A walker has left a handprint on a snow- covered tree trunk on Grosser Feldberg mountain in the Taunus mountain range, Germany, 16 January 2017. (Photo by Frank Rumpenhorst/DPA)