“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)

People take part in the Classic Ride Rally in downtown Valencia, eastern Spain, 23 November 2014. Some hundred people on classic bikes from the 20's to the 70's participated in the rally. (Photo by Kai Foersterling/EPA)

Spectators cheer as the United Launch Alliance Delta 4-Heavy rocket, with NASA's Orion spacecraft mounted atop, lifts off from the Air Force Station, December 5, 2014, in Cape Canaveral, Fla. (Photo by Smiley N. Pool/AP Photo/Houston Chronicle)

Saraa Mutawkil (R), 18, practises boxing at Al Rabie club in Omdurman May 10, 2016. (Photo by Mohamed Nureldin Abdallah/Reuters)

Indian men stand around sword fish for sale at a harbour a harbour in Chennai on June 5, 2016, as fishermen return with their catch after a 45-day fishing ban on the east coast of India. Authorities in the southern Indian state of Tamil Nadu had imposed a 45-day ban on fishing by mechanised vessels to protect marine life, with only “country boats” operating within five nautical miles off the coast. (Photo by Arun Sankar/AFP Photo)

Wild weather drenches tourists, Sydney, Australia on March 7, 2017. A series of photographs as tourists take a soaking on Sydney's iconic Manly Ferry sailing big swells near Sydney's North Head. The Weather Bureau warns of large and powerful surf conditions expected to be hazardous for coastal activities such as rock fishing, swimming and surfing. (Photo by Hugh Peterswald/Pacific Press via ZUMA Wire/Rex Features/Shutterstock)

Vets of Animals Asia Foundation's Vietnam Bear Rescue Center hold a paw of a sun bear as they check its health while it is rescued from a Vietnamese family in Nam Dinh province, south of Hanoi, Vietnam August 18, 2016. A man in northern Vietnam has voluntarily handed over a bear his family had caged for seven years to an animal rights organization, which will take it to a nearby sanctuary. (Photo by Reuters/Kham)

An armed youth loyal to the Houthi movement takes part in a protest against the Saudi-backed exiled government deciding to cut off the Yemeni central bank from the outside world, in the capital Sanaa, Yemen August 25, 2016. (Photo by Mohamed al-Sayaghi/Reuters)