The Northern Lights glow green in a spectacular light show above a field of trees frozen solid with snow. (Photo by Jaak Sarv/Solent News & Photo Agency)

A woman plays with a kitten inside of a line house in downtown Shanghai April 12, 2015. (Photo by Carlos Barria/Reuters)

A walruses at Hagenbeck Zoo in Hamburg, Germany on July, 7, 2015. (Photo by Werner Struss/Startraks action)

The carcass of a fattened pig, winner of the “holy pig” contest, is attached to a metal frame during a sacrificial ceremony in Sanxia district, in New Taipei City, Taiwan February 1, 2017. The winner of Taiwan's “holy pig” ceremony on Thursday defended the lunar new year tradition against critics who argue the fattened animals are raised under cruel conditions. (Photo by Tyrone Siu/Reuters)

A vendor sleeps at his vegetables shop at a main market in Colombo, Sri Lanka May 31, 2016. (Photo by Dinuka Liyanawatte/Reuters)

In a new project, an international group of photographers have joined forces to use their powerful images to raise awareness and funds to help stop the illegal wildlife trade. Here: Fennec foxes are captured for the illegal pet trade. This three-month-old pup was for sale in a market in southern Tunisia. (Photo by Bruno D'Amicis/Photographers Against Wildlife Crime/Wildscreen/The Guardian)

A “super blood blue moon” is seen during an eclipse behind an elephant statue at a temple in Bangkok, Thailand, January 31, 2018. (Photo by Athit Perawongmetha/Reuters)

A man impersonating North Korean leader Kim Jong Un gestures as he stands before North Korean cheerleaders attending the Unified Korean ice hockey game against Japan during the Pyeongchang 2018 Winter Olympic Games at the Kwandong Hockey Centre in Gangneung on February 14, 2018. (Photo by Yelim Lee/AFP Photo)