Elephants spray tourists with water in celebration of the Songkran water festival in Thailand's Ayutthaya province, about 80 km (50 miles) north of Bangkok, April 9, 2014. (Photo by Rungroj Yongrit/EFE)

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)

US marines watch the mushroom cloud from an atomic explosion rise above the Yucca flats, Nevada during a US nuclear weapons test. (Photo by Keystone/Getty Images). USA, 1945

A visitor walks past an installation artwork entitled “Confuciuse” which combines the word “Confucius” and “confuse” in the contemporary art exhibition at “Fun and Art” Festival on December 13, 2008 in Xian of Shaanxi Province, China. (Photo by China Photos/Getty Images)

Finia, a visiting student from Hanover, cools off under a water sprinkler in front of the Chancellery on June 10, 2010 in Berlin, Germany. (Photo by Sean Gallup/Getty Images)

Linda Cerruti of Italy competes in the Synchronized Swimming Solo Tech preliminary round during Day Two of the 14th FINA World Championships at the Oriental Sports Center on July 17, 2011 in Shanghai, China. (Photo by Ezra Shaw/Getty Images)

The moon shines through trees at a United Nations displacement camp at dusk on March 14, 2011 in Ras Jdir, Tunisia. (Photo by Dan Kitwood/Getty Images)

People take part in the Classic Ride Rally in downtown Valencia, eastern Spain, 23 November 2014. Some hundred people on classic bikes from the 20's to the 70's participated in the rally. (Photo by Kai Foersterling/EPA)