Rwandan refugees cross the Rusumo border to Tanzania from Rwanda carrying their belongings, goats, mattresses and cows, May 30, 1994. The bloodshed that claimed 800,000 Tutsi and moderate Hutu lives began 25 years ago on April 7, 1994, when a plane carrying Rwandan President Juvenal Habyarimana, Burundi President Cyprien Ntaryamira and a French air crew was shot down. (Photo by Jeremiah Kamau/Reuters)

Members of the Iraqi Army fire towards Islamic State militant positions at the south of Mosul, Iraq December 10, 2016. (Photo by Alaa Al-Marjani/Reuters)

A kid wearing rollerblades hitches a ride via motorbike, in Port-au-Prince, Haiti, Sunday, October 25, 2015. The country held the first-round presidential vote Sunday. Haitians chose between 54 presidential hopefuls and a slew of legislative and municipal candidates. (Photo by Ricardo Arduengo/AP Photo)

Children feed a giraffe at Pairi Daiza wildlife park, a zoo and botanical garden in Brugelette, Belgium, May 25, 2015. (Photo by Francois Lenoir/Reuters)

A fisherman boats in Chao Lake where thick cyanobacteria gather on the surface on August 5, 2015 in Chaohu, Anhui Province of China. As high temperature came in summar, part of water in Anhui Province's Chao Lake breeds large tracts of cyanobacteria which not only brought pollution to sense of smell, but also affected people's life. (Photo by ChinaFotoPress/ChinaFotoPress via Getty Images)

Hindu devotees, their bodies pierced with lemon and paladai, or bowl with a spout mainly used to feed milk to infants, wait to participate in a procession to mark Shivratri, or the night of Shiva, in Chennai, India, Wednesday, February 18, 2015. Such processions are held as an offering and show of devotion by devotees on the day dedicated to the worship of Lord Shiva, the Hindu god of destruction. (Photo by Arun Sankar K./AP Photo)

Two women lighting cigarettes on a tennis court in Essex, England circa 1930's. (Photo by Keystone View/FPG/Getty Images)

Female bodybuilders prepare to compete in the “Miss Bikini” category of the NABA/WFF Asia-Seoul Open Championship in Seoul on April 17, 2016. (Photo by Ed Jones/AFP Photo)