A one-month-old wolf cub ululate as zookeeper Luo Yong plays guitar at the Chongqing Yongchuan Safari Park on March 27, 2008 in Chongqing, China. Luo has worked as a keeper in the wolf zone of the park after he graduated university. Luo has developed a special way to communicate with the wolves by trying to imitate the noises they make. He also teaches wolf cubs to ululate and some wolves will howl along when he plays guitar. (Photo by China Photos/Getty Images)

Boys play football in a shantytown of Olinda, about 18 km from Recife in northeastern Brazil, on June 18, 2013 as the FIFA Confederations Cup Brazil 2013 football tournament is being held in the country. The historic centre of Olinda is listed as an UNESCO World Heritage Site. (Photo by Yasuyoshi Chiba/AFP Photo)

Young men play basketball on an improvised court wedged between a construction site and the shells of once grand colonial homes in Havana, July 20, 2015. As much as the young in Cuba welcome political opening and economic reform, such changes are unlikely to filter down to their lives anytime soon. (Photo by Meridith Kohut/The New York Times)

A picture taken on March 9, 2017, shows a boy playing with a cat next to a 1948 Buick parked outside the home of Mohammad Mohiedine Anis in the formerly rebel-held al-Shaar neighbourhood. (Photo by Joseph Eid/AFP Photo)

Actress Kerry Washington, Harvard University's Hasty Pudding Theatricals' Woman of the Year, throws wine in the face of an actor playing Republican presidential candidate Donald Trump, Thursday, January 28, 2016, as she is roasted in Cambridge, Mass. (Photo by Elise Amendola/AP Photo)

Women play soccer as the Tungurahua volcano spews a column of ash during an eruption in Huambalo, Ecuador, Saturday, March 5, 2016. Tungurahua is 16,480 feet (5,023 meters) high and has been active since 1999. (Photo by Dolores Ochoa/AP Photo)

Penitent Jerry Mazon, 9, wears his “Morions” mask while playing with his baby brother during Holy Week celebrations in Mogpog, Marinduque in central Philippines March 22, 2016. (Photo by Erik De Castro/Reuters)

In this Monday, June 20, 2016 photo, a Palestinian girl plays in a barrel as her mother bakes bread for a Ramadan dinner at their house in el-Zohor slum, on the outskirts of Khan Younis refugee camp, southern Gaza Strip. (Photo by Khalil Hamra/AP Photo)