A woman photographs a Norwegian spruce Christmas tree from Oslo after it was lit at Trafalgar Square in central London, December 4, 2014. (Photo by Toby Melville/Reuters)

The aurora borealis, or the northern lights occur over Derwentwater, near Keswick, England, Thursday October 8, 2015. The northern lights are the result of collisions between gaseous particles in the Earth's atmosphere with charged particles released from the sun. (Photo by Owen Humphreys/PA Wire via AP Photo)

Early morning storms over the Masai Mara National Reserve, Kenya on August 26, 2016. (Photo by Action Press/Rex Features/Shutterstock)

An Indonesian vendor fixes a headscarf on a mannequin at a market in Jakarta in this December 21, 2006 file photo. (Photo by Reuters/Beawiharta)

A climber walks on the ridge beneath the eastern peak of the Gamsberg (2385 meters above sea level) near Grabs, Switzerland, Friday, October 3, 2014. (Photo by Gian Ehrenzeller/AP Photo/Keystone)

People hold umbrellas as they walk past a flooded street in Taiyuan, Shanxi Province, China, July 19, 2016. (Photo by Reuters/China Daily)

This greedy piglet was isolated from the rest of its litter by the farmer who named it Hitler after it tried to grab all the food at feeding time. (Photo by R J Lewis/Getty Images). 1942

A child plays with a soap bubble on the city hall plaza on March 14, 2015 in Paris. (Photo by Dominique Faget/AFP Photo)