“Aurora Hunters”. Photographers taking part in a photography tour on the Lofoten Islands in Norway, pull over on the side of the road to take a photo of their first ever Aurora Borealis after spotting it from their tour bus. Photo location: Rystad, Lofoten Islands, Norway. (Photo and caption by Mark Gee/National Geographic Photo Contest)

A member of the mainly Christian “anti-balaka” (anti-machete) militia trains in the Boeing neighbourhood of Bangui, Central African Republic, on February 24, 2014. (Photo by Fred Dufour/AFP Photo)

Pedestrians look at “doll” model Lulu Hashimoto standing on the street during a photo opportunity for Reuters in Tokyo, Japan August 23, 2017. (Photo by Kim Kyung-Hoon/Reuters)

A woman walks with her baby past a PM militarized police soldier in position and aiming his rifle in Rocinha favela in Rio de Janeiro, Brazil on September 23, 2017. Although shooting was reported in the early hours of Saturday in Rocinha – for the seventh day running – officials said that Friday's deployment of 950 soldiers to reinforce police had brought the crisis under control. (Photo by Carl De Souza/AFP Photo)

A Bangladeshi girl plays on a swing, in Dhaka, Bangladesh, December 27, 2016. (Photo by Mohammad Ponir Hossain/Reuters)

Base jumpers leap from the 300-metre high skydeck of Malaysia's landmark Kuala Lumpur Tower against the backdrop of the city's skyline on October 3, 2016 during the annual International KL Tower Base-Jump event. (Photo by Manan Vatsyayana/AFP Photo)

A skydiver dressed as Santa Claus prepares to leap out of a plane as 155 tandem skydivers set a new Guinness World Record over eight hours, over the Australian city of Wollongong, December 17, 2016. (Photo by Jason Reed/Reuters)

“Winter Climbing from inside Ben Nevis”. The view from inside the mountain, as a winter climber passes through the cave on Minus Three gully. Photo location: Ben Nevis, Fort William, Scotland. (Photo and caption by Daniel Wildey/National Geographic Photo Contest)