“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)

A partially burned American flag lies on the street near the spot where Michael Brown was killed before an event to mark the one year anniversary of his killing in Ferguson, Missouri August 9, 2015. (Photo by Rick Wilking/Reuters)

“Joker” movie production tries to hide Joaquin Phoenix's clown make-up and green hair with umbrella and a long black cloth over his head as he was walking with the help of assistant and bodyguard to the set of “Joker” filming at a Bronx train station on September 22, 2018. (Photo by The Mega Agency)

Revelers, covered in coloured powder, celebrate, during a Holi Run Festival in Madrid, Spain, Sunday, April 12, 2015. Thousands of revelers took part in the festival that includes a mini marathon. The festivals are fashioned after the Hindu spring festival Holi, which is mainly celebrated in the north and east of India. (Photo by Andres Kudacki/AP Photo)

A Saudi soldier fires a mortar towards Houthi movement position, at the Saudi border with Yemen April 21, 2015. (Photo by Reuters/Stringer)

A hot air balloon floats over farm fields south of Washington, Ill., as the sun slips behind clouds on the autumn afternoon of Wednesday, September 24, 2014. (Photo by Ron Johnson/AP Photo/Peoria Journal Star)

In this June 17, 2014 photo, a North Korean man takes shelter in the rain next to long propaganda billboards in the town of Samjiyon in North Korea's Ryanggang province. The Associated Press was granted to embark on a weeklong road trip across North Korea to the country’s spiritual summit Mount Paektu. The trip was on North Korea's terms. An AP reporter and photographer couldn't interview ordinary people or wander off course, and government “minders” accompanied them the entire way. (Photo by David Guttenfelder/AP Photo)

Vanessa Silva, 38, feeds macaws that fly to her apartment window every day looking for food, in Caracas, Venezuela, on November 24, 2014. A group of gold-and-royal blue birds poked their heads through Silva’s window, as if saying “I’m here, is anyone home?” “I’d seen them flying when I was down on the street, and I thought ‘Oh how pretty,’” the 38-year-old said, a macaw eating out of her hand. (Photo by Ariana Cubillos/AP Photo)