Palestinian schoolboys sit in the trunk of a car as they go to school on a rainy day in Khan Younis, in the southern Gaza Strip, October 7, 2015. (Photo by Ibraheem Abu Mustafa/Reuters)

A woman wearing a mask walk in a street in a Yonghegong Lama temple compound seen shrouded in smog in Beijing, China, 30 November 2015. Beijing issued an orange alert for heavy smog 30 November, the highest level this year. Authorities in the Chinese capital warned of 'severe pollution' and advised the capital's 20 million inhabitants to stay indoors. (Photo by How Hwee Young/EPA)

A man drinks at a "colored" water cooler in a streetcar terminal in Oklahoma City, July 1939. (Photo by Reuters/Library of Congress)

A supporter of Venezuela's President Nicolas Maduro, with a doll depicting late Venezuela's President Hugo Chavez on his hat, reacts as he stands at the Plaza Bolivar near the building housing the National Assembly in Caracas, January 5, 2016. (Photo by Christian Veron/Reuters)

Palestinian children warm themselves by a fire on a stormy day at Shati (beach) refugee camp in Gaza City January 18, 2016. (Photo by Mohammed Salem/Reuters)

South Korea's Black Eagles aerobatics team performs an aerial display forming a Ying and Yang logo during the Singapore Airshow at Changi exhibition center in Singapore on February 16, 2016. (Photo by Roslan Rahman/AFP Photo)

A picture made available on 07 March 2016 shows visitors petting and holding a Fennec fox, native to the Sahara, in the petting room at the Little Zoo Cafe, a business built to capitalize on Thais' love for exotic animals, and food, on the outskirts of Bangkok, Thailand, 05 March 2016. The cafe boasts Fennec foxes, Meerkat, native to parts of Africa, Silver Fox, Raccoon and Chinchillas, along with a menu of Thai food and Cheesecake, among other sweet deserts. Nature is a faraway fantasy in the bustling exhaust-filled cement city of Bangkok, fuelling a demand to own and be close to exotic pets. The trend to be near to a species that was once wild, in a city environment, far from the natural setting, has drawn criticism but continues to grow. (Photo by Barbara Walton/EPA)

A man plays to the cameras as racegoers make their way home at the end of Ladies Day the second day of the Aintree Grand National Festival meeting on April 8, 2016 in Aintree, England. Today is Fabulous Friday and Ladies Day of the three-day meeting of the world famous Grand National Festival where fashion and dressing to impress is as important as the racing. (Photo by Christopher Furlong/Getty Images)