“A Mothers Tail”. A baby cub pulls on his mother's tail to get attention. Photo location: Masai Mara, Kenya. (Photo and caption by Tori Marsh/National Geographic Photo Contest)

A wide-angle view shows the ascent of the shuttle Challenger on January 28, 1986. In the seconds after ignition, the rocket engines' hot blast began the process of destruction. (Photo by NASA)

A seafood vendor moves a giant swordfish to his stall at a market in Qingdao, Shandong province, China, September 12, 2015. The 4.1-metre-long (13.5 feet) swordfish, weighed about 309.5 kilograms (682 lbs), was caught by local fishermen on Friday, local media reported. (Photo by Reuters/Stringer)

Photographer Jim Zielinski from Florida, USA, captured this hilarious moment when a squirrel spied a tasty treat inside a novelty horse's head bird feeder in his back garden. (Photo by Jim Zielinski/Caters News)

Vladimir Putin shows a hold to a young judo wrestler at the Regional Judo Center at the Arena Sports Complex in the Siberian city of Kemerovo on January 24, 2012, during his visit to the region. Putin is known for his passion for judo, in which he has a black belt. (Photo by AFP Photo/STR)

Deputies in the Ukrainian parliament brawled in the chamber on Tuesday, April 8, 2014 after a communist leader accused nationalists of playing into the hands of Russia by adopting extreme tactics early in the Ukrainian crisis. Two deputies from the Svoboda far-right nationalist party took exception to the charges by communist Petro Symonenko and seized him while he was talking from the rostrum. (Photo by Valentyn Ogirenko/Reuters)

American actress Nicola Peltz poses on the red carpet as she arrives for the world premiere of the movie “Transformers 4: Age of Extinction” in Hong Kong Thursday, June 19, 2014. The latest installment in the blockbuster series of “Transformers” films is making its world premier not in the usual entertainment hubs of Los Angeles or New York but in the wealthy Chinese metropolis of Hong Kong, the latest sign of Hollywood's increasing focus on China's booming film market. (Photo by Kin Cheung/AP Photo)

Lightning illuminates a thundercloud as a storm front hits the North Sea region near Westerhever, northern Germany, on August 11, 2014. (Photo by Daniel Reinhardt/AFP Photo/DPA)