A North Korean soldier throws a stone towards a photographer on the banks of the Yalu River in the North Korean town of Sinuiju, opposite the Chinese border city of Dandong October 21, 2006 in Sinuiju, Democratic People's Republic of Korea. (Photo by Cancan Chu/Getty Images)

A man walks next to a section of the wall separating Mexico and the United States, on the outskirts of Ciudad Juarez, Mexico, November 12, 2016. (Photo by Jose Luis Gonzalez/Reuters)

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 pro-Russian supporter with the Russian national flag on her shoulders takes part in a meeting in Simferopol, March 6, 2014. Crimea's parliament voted to join Russia on Thursday and its Moscow-backed government set a referendum within 10 days on the decision in a dramatic escalation of the crisis over the Ukrainian Black Sea peninsula. (Photo by Vasily Fedosenko/Reuters)

Refugee children play with a stuffed toy at a muddy makeshift camp at the Greek-Macedonian border, near the village of Idomeni, Greece March 15, 2016. (Photo by Alexandros Avramidis/Reuters)

A man covered with thermal blanket walks along railway tracks beside an improvised refugee camp on the border line between Macedonia and Serbia near the northern Macedonian village of Tabanovce, Thursday, March 10, 2016. Around 1.500 migrants and refugees are stranded at Tabanovce transit center for refugees in northern Macedonia. (Photo by Boris Grdanoski/AP Photo)

Ukrainian state emblem is seen on a gun's holster as soldiers guard naval base in the village of Novoozernoye, some 91 km west of Crimean capital Simferopol, Ukraine, on Monday, March 3, 2014. Ukraine says Russian forces controlling the strategic region of Crimea are demanding that the crew of two Ukrainian warships in Sevastopol's harbor must surrender. (Photo by Ivan Sekretarev/AP Photo)

An Afghan girl carries water on her back as she climbs a hill in Kabul, Afghanistan February 20, 2017. A growing population is straining water supplies in Afghanistan's capital, forcing those who can afford it to dig unregulated wells ever deeper to tap a falling water table. Finding water in arid Afghanistan is virtually always a challenge, but a drop in the groundwater level in Kabul caused by overuse and drought is making it even more difficult for residents, especially the poor. (Photo by Omar Sobhani/Reuters)