Students exercise in body training at Bishan Vocational Education Center in Chongqing, southwest China, January 13, 2016. These students were trained to be stewardesses of the high-speed train. (Photo by Xie Jie/Xinhua)

Lightning streaks across the sky as lava flows from a volcano in Eyjafjallajokul April 17, 2010. (Photo by Lucas Jackson/Reuters)

Salvadoran indigenous participate in the International Day of the Indigenous Peoples at Divino Slavador square in San Salvador, El Salvador, 09 August 2016. (Photo by Oscar Rivera/EPA)

A protester clashes with a police officer in Athens' central Syntagma (Constitution) Square in this June 15, 2011 file photo. Greece triggered the regional financial crisis in 2009 when a far higher budget deficit than previously calculated emerged. The collapse of talks with creditors in Paris last November set off a month-long sequence of events leading to elections this week and proving Greece is still the region's weak link. The vote is expected to be won by Syriza, a far-left party opposed to the bailout, worrying investors and creditors alike. (Photo by Yannis Behrakis/Reuters)

A riot policeman punches Greek photojournalist Tatiana Bolari during a demonstration in Athens' Syntagma (Constitution) square October 5, 2011. Police officers attacked several members of the press covering protests, injuring at least two members of the media. (Photo by Yannis Behrakis/Reuters)

Rescue workers stand next to TK Bremen cargo ship which ran aground during a powerful storm, spilling oil off the coast of France's northwestern region of Brittany as it lies stranded on Kerminihy beach in Erdeven, on December 16, 2011. (Photo by Damien Meyer/AFP Photo)

A girl carries utensils after filling them with water from a pipe that supplies water to trains at a railway station on the outskirts of Agartala, India, February 28, 2017. (Photo by Jayanta Dey/Reuters)

Rag pickers collect recyclable material at a garbage dump in New Delhi November 19, 2014. (Photo by Ahmad Masood/Reuters)