Black-headed gulls sit on pickets at a riverside in Tokyo, Japan, December 27, 2015. (Photo by Toru Hanai/Reuters)

Devotees bow to a passingTibetan Buddhist monk on his way to take part in a special prayer during Monlam or the Great Prayer rituals on March 5, 2015 at the Labrang Monastery, Xiahe County, Amdo, Tibetan Autonomous Prefecture, Gansu Province, China. Labrang Monastery is one of the six great monasteries of the Gelug school of Tibetan Buddhism and one of the largest outside of the Tibetan Autonomous Region. Monlam, the most important prayer event for many Tibetans was banned during the Cultural Revolution in China but once again in recent years it is celebrated in many areas. (Photo by Kevin Frayer/Getty Images)

A member from the Iraqi security forces beats an Islamic State insurgent, who was captured in Tikrit April 1, 2015. Iraqi troops and Shi'ite paramilitary fighters were battling Islamic State on Wednesday in northern Tikrit, which officials described as the Sunni Muslim militant group's last stronghold in the city. (Photo by Alaa Al-Marjani/Reuters)

A hippopotamus performs during a show at the circus in Krasnoyarsk, Siberia, Russia, July 7, 2016. (Photo by Ilya Naymushin/Reuters)

Cambodian children sleep on a pavement at a park in Phnom Penh on July 8, 2016. (Photo by Tang Chhin Sothy/AFP Photo)

Men carry a dog, wearing a costume and seated on a stool, as a form of respect as they believe that dogs found water for their ancestors, during a local festival for the Miao ethnic minority in Jianhe county, Guizhou Province, China, August 14, 2016. (Photo by Reuters/China Daily)

Against the scorching sun, a hungry jackal chases a flock of birds looking for a quick morning snack. Taken in South Africa's Kgalagadi Transfrontier National Park, these images capture the moment a lone hunter tries, and then succeeds, in his pursuit. (Photo by John Mullineux/Solent News)

Cast member Ana de Armas poses during a photocall for the film “Hands of stone” out of competition at the 69th Cannes Film Festival in Cannes, France, May 16, 2016. (Photo by Regis Duvignau/Reuters)