Chinese Kazakh eagle hunters sit on horseback as they travel to a local competition on January 29, 2015 in the mountains of Qinghe County, Xinjiang, northwestern China. The festival, organised by the local hunting community, is part of an effort to promote and grow traditional hunting practices for new generations in the mountainous region of western China that borders Kazakhstan, Russia and Mongolia. The training and handling of the large birds of prey follows a strict set of ancient rules that Kazakh eagle hunters are preserving for future generations. (Photo by Kevin Frayer/Getty Images)

A young girls holds a ballot during the Greek referendum in Athens on July 5, 2015. Greek voters headed to the polls today to vote in a historic, tightly fought referendum on whether to accept worsening austerity in exchange for more bailout funds, in a gamble that could see it crash out of the euro. (Photo by Aris Messinis/AFP Photo)

In this timed-exposure night photo taken early on February 12, 2017, Mount Sinabung volcano spews reddish smoke and ash, as seen from the Karo district in North Sumatra province. Activity levels have increased in the past week, with Sinabung shooting hot ash clouds into the sky dozens of times, according to the local volcano monitoring agency. (Photo by AFP Photo/Stringer)

An employee of a bakery talks on his mobile while balancing on his head a tray of freshly baked bread from a local bakery in a street in Cairo, Egypt, January 12, 2016. (Photo by Asmaa Waguih/Reuters)

The sculpture “It Takes Two to Tango” by Scottish sculptor David Mach is seen in front of the headquarters of the CMA-CGM shipping company office tower in the port of Marseille, France, March 15, 2016. (Photo by Jean-Paul Pelissier/Reuters)

A girl salutes to visitors before a show at the Mangyongdae Children's Palace in central Pyongyang, North Korea May 5, 2016. Pyongyang held a gala of song and dance performances by local school children on May 5 for visiting delegations of foreign journalists and tourists at the Mangyongdae Children's Palace. The event included orchestral, choir, and acrobatic performances, many of them with political undertones. The Seventh Worker's Party Congress commences on May 6, 2016. (Photo by Damir Sagolj/Reuters)

Alex Plunkett, left, and Sean Hart, both of Arlington, Va., join hundreds participating in the annual International Pillow Fight Day on April 5. Massive pillow fights broke out on the Mall in Washington and in cities around the world. (Photo by Marvin Joseph/The Washington Post)

A traffic police woman whistles at a pedestrian, Monday, July 27, 2015, in Pyongyang, North Korea where its citizens are having a one-day national holiday to celebrate the country's 62nd anniversary of the armistice that ended the Korean War. (Photo by Wong Maye-E/AP Photo)