Yaks head towards the Everest base camp in Solukhumbu District April 28, 2014. (Photo by Navesh Chitrakar/Reuters)

An undercover police officer, who had been marching with anti-police demonstrators, aims his gun at protesters after some in the crowd attacked him and his partner in Oakland, California December 10, 2014. Police said more than 100 demonstrators marched in Berkeley, California, which has a history of social activism. Under cloudy skies, turnout was smaller than earlier in the week, when demonstrators in the area threw rocks at police and shut down a major freeway. (Photo by Noah Berger/Reuters)

A visitor poses for a photograph in front of a 3D painting depicting a Japanese Imperial army soldier at a 3D art gallery in Beijing January 16, 2015. (Photo by Kim Kyung-Hoon/Reuters)

Men eat oranges from a push cart along a road as a vehicle travels past them in Karachi January 22, 2015. (Photo by Akhtar Soomro/Reuters)

With a presence in nearly every city and town across Iran, the paramilitary Basij volunteer corps has an ever-increasing influence on life in the Islamic Republic. Authorities created the Basij, which means mobilization in Persian, just after the country's 1979 Islamic Republic. It is part of Iran's powerful Revolutionary Guard. Photo: In this Thursday, August 22, 2013 photo, a female member of the Basij paramilitary militia aims a rifle as a trainer looks over her shoulder in Tehran, Iran. (Photo by Ebrahim Noroozi/AP Photo)

Breitling Wingwalker Freya Paterson, from Liverpool, UK, flies above Kuwait City's iconic Water Towers with pilots David Barrell and Martyn Carrington, on March 6, 2014. The team loop and roll up to 160 mph enduring G-forces of 4-5g. Crowds are expected to line the Kuwaiti coastline to catch a glimpse of the Wingwalking team on Saturday, March 8, 2014, to mark the opening of the first dedicated boutique in the city for the prestigious watch brand. (Photo by Katsuhiko Tokunaga/Breitling)

Some 300 girls and women in India still practise open defecation. Over half the country’s population, 800 million people, do not have access to a toilet that meets basic standards. (Photo by Poulomi Basu/WaterAid)

The Euro sculpture is partially reflected in a puddle on a cobblestone pavement in front of the headquarters of the European Central Bank in Frankfurt on Jan. 21. (Kai Pfaffenbach/Reuters)