Devotees ride on the roof of a train as they return to the city after attending the final prayers on the first phase of Bishwa Ijtema in Dhaka January 11, 2015. Hundreds of thousands of pilgrims congregated in the Bangladeshi capital Dhaka as the first phase of this year's Bishwa Ijtema, one of the biggest Islamic gatherings in the world after the Haj in Saudi Arabia, came to an end. (Photo by Reuters/Stringer)

Walkers cross the river Waalbrug during the first day of the 98th annual four-days walking event, the “Vierdaagse” in Nijmegen, Netherlands, July 15, 2014. The “Nijmeegse Vierdaagse” is an annual public four-day field march which is held since 1909 in the third week of July. (Photo by Erik van 't Wout/EPA)

A protester uses molotov cocktails against riot police during May Day protests on May 1, 2010 in Athens, Greece. (Photo by Milos Bicanski /Getty Images)

Hot air balloons take to the skies as they participate in the mass assent at sunrise on the second day of the Bristol International Balloon Fiesta on August 11, 2017 in Bristol, England. More than 130 balloons have gathered for the four day event, now in its 39th year and now one of Europe's largest annual hot air balloon events, being hosted in the city that is seen by many as the home of modern ballooning. (Photo by Matt Cardy/Getty Images)

In this photo taken on August 26, 2017, a contestant of the “fantasy” category prepares to be judged during the Daegu International Bodypainting Festival in Daegu, South Korea. The bodies of dozens of female models turned into living canvases this weekend as they allowed delicate brush strokes and flamboyant illustrations to cover up their bare skin. They are part of the 2017 Daegu International Bodypainting Festival along with top artists from 10 countries that runs until August 27 in South Korea's southeastern city of Daegu. (Photo by Ed Jones/AFP Photo)

The Japanese punk rock garage quartet Otoboke Beaver perform at Maggie Mae's at the South by Southwest (SXSW) Music Film Interactive Festival 2017 in Austin, Texas, U.S., March 17, 2017. (Photo by Brian Snyder/Reuters)

Sarah Bui poses for photographer, Brian Le around blossoming cherry trees, near the Tidal Basin on Thursday March 23, 2017 in Washington, DC. (Photo by Matt McClain/The Washington Post)

A model falls over on the runway in a design by Victoria Bliss during the Project NextGen show at Mercedes-Benz Fashion Week Resort 18 Collections at Carriageworks on May 16, 2017 in Sydney, Australia. (Photo by Stefan Gosatti/Getty Images)