Participants compete in the Mud Day Race extreme run competition at El Goloso military base, outside Madrid, Spain, June 11, 2016. Thousands of athletes got covered in mud as they celebrated International Mud Day running a 13-kilometer obstacle course on a sunny Saturday with heatwave-like temperatures up to a 29 degrees Celcius (around 84 degrees Fahrenheit). (Photo by Juan Medina/Reuters)

In this September 4, 1963, file photo, a police officer carries off a demonstrator holding a Confederate flag after a group of demonstrators protested enrollment of two African-Americans at Ramsay High School in Birmingham, Ala. The Confederate battle flag has been removed from South Carolina's Statehouse grounds, in the wake of the massacre of nine African-Americans, including a state senator, at an historic black church in Charleston in June 2015. (Photo by AP Photo)

A dancer performs during the Gymnastics Rio Gala on Day 12 of the 2016 Rio Olympic Games on August 17, 2016 in Rio de Janeiro, Brazil. (Photo by Clive Brunskill/Getty Images)

A motorized three-wheeled taxi carrying Muslim students drives past the Starbucks cafe where Thursday's attack occurred in Jakarta, Indonesia, on Friday, January 15, 2016. A day after attackers detonated bombs and engaged in gunbattles with police in the central part of Indonesia's capital, Jakarta tried to get itself back on track. (Photo by Dita Alangkara/AP Photo)

Characters dressed as Elmo and Cookie Monster who pose for tips take a photo by request from a tourist (2nd R, black pants) in Times Square in the Manhattan borough of New York City, January 29, 2016. (Photo by Rickey Rogers/Reuters)

Tim Anderson final balanced rock stack in the Llano River. Tim Anderson, rock balancing “pro” from Pennsylvania, carefully worked to balance his stack on a dry spot in the Llano river Saturday March 12, 2016. He was an honored guest of the festival and enjoyed visiting Texas so he came for another year. The river was higher this year because of the rains so the balancers could not get to the better rock that were available last year. (Photo by Nell Carroll/American-Statesman)

A woman takes a selfie picture as Turkish Kurds gather as part of Newroz celebrations in Diyarbakir, on March 21, 2016. Nowruz, the Farsi-language word for “New Year”, is an ancient Persian festival, celebrated on the first day of spring, on March 21, in Central Asian republics, Iraq, Turkey, Afghanistan and Iran. (Photo by Ilyas Akengin/AFP Photo)

An Zi, is squashed amongst other commuters in a subway train on his way to work in Beijing, China, November 12, 2015. An, a movie producer, moved to Dongsanqi village in Changping this year. His commute to work can take about 2 hours, with transportation costs topping 200 yuan a month, or about a fifth of his monthly rent. (Photo by Jason Lee/Reuters)