Motorcycling, Gotland Grand National 2016 endure race, Gotland, Sweden on October 29, 2016. Riders compete. (Photo by Soren Andersson/Reuters/TT News Agency)

Students feed fruit to an elephant during Thailand's National Elephant Day in the ancient Thai capital Ayutthaya March 13, 2015. Thais honoured the elephant on Friday with special fruits and Buddhist ceremonies across the country to pay homage to their national animal. (Photo by Athit Perawongmetha/Reuters)

A female participant of the Bela Negara – “defend the nation” – programme applies camouflage face paint on another participant's face at a training centre in Rumpin, Bogor, West Java, Indonesia June 2, 2016. (Photo by Darren Whiteside/Reuters)

Chinese hostesses, who serve the delegates of the Chinese People's Political Consultative Conference and National People's Congress, have souvenir photos taken in front of the Great Hall of the People during sessions of the CPPCC and NPC held in Beijing, China Tuesday, March 4, 2014. (Photo by Andy Wong/AP Photo)

Tanzania, 1964. A touching moment between primatologist and National Geographic grantee Jane Goodall and young chimpanzee Flint at Tanzania's Gombe Stream Reserve. (Photo by Hugo van Lawick via National Geographic)

People of pro-government groups, with Russian flags, dance marching through downtown Moscow to mark People's Unity Day, a public holiday, in Russia, on Tuesday, November 4, 2014. Russia marks National Unity Day on November 4 to celebrate the defeat of Polish invaders in 1612. (Photo by Ivan Sekretarev/AP Photo)

An injured fan is helped by a riot policeman during clashes between Red Star Belgrade and Partizan Belgrade fans in the stadium before the teams' Serbian Superliga soccer match in Belgrade, April 25, 2015. Serbian league leaders Partizan Belgrade held champions and bitter city foes Red Star to a 0-0 draw in a derby match marred by bad crowd trouble before kickoff on Saturday. The start was delayed for 45 minutes after home Red Star supporters pelted riot police with seats and flares, forcing officers to retreat from the north tier that houses the club's diehard fans. (Photo by Marko Djurica/Reuters)