Cuban soldiers receive combat training at the Cadets School “Antonio Maceo” November 28, 2001, 30 kilometers East of Havana. (Photo by Jorge Rey/Getty Images)

Two girls are detained outside the Currys electrical store in Brixton on August 8, 2011 in London, England. Widespread rioting and looting took place across many parts of London in the early hours of Monday morning in a reaction to earlier rioting in Tottenham in North London. Major disturbances broke out late on Saturday night in Tottenham and the surrounding area after the killing of Mark Duggan, 29 and a father-of-four, by armed police in an attempted arrest on August 4. (Photo by Dan Kitwood/Getty Images)

A zebra walks through the recently flooded Safari Park located at Safari World November 2, 2011 in Bangkok, Thailand. (Photo by Paula Bronstein /Getty Images)

Women walk through the snow on Wimbledon common with their dogs on February 10, 2012 in London, England. The Met Office cold weather alert remains at Level 3 as southern parts of England continue to suffer from cold weather and freezing conditions, with further snowfall overnight. (Photo by Peter Macdiarmid/Getty Images)

Students in Aone’s elementary school during break in between the class on April 9, 2015. The school has only six students, two of whom are from the same family. Similarly small schools can be found throughout Japan. (Photo by Ko Sasaki/The Washington Post)

A man carries a dog and wades through a flooded street in Chennai, in the southern Indian state of Tamil Nadu, Wednesday, December 2, 2015. Weeks of torrential rains have forced the airport in the state capital Chennai to close and have cut off several roads and highways, leaving tens of thousands of people stranded in their homes, government officials said Wednesday. (Photo by AP Photo)

The Jade Belt Bridge, also known as the Camel's Back Bridge, is an 18th-century pedestrian Moon bridge located on the grounds of the Summer Palace in Beijing, China. It is famous for its distinctive tall thin single arch.

Paul, 9, dumps a bucket of water over his head at a fountain near government buildings during hot weather on July 1, 2015 in Berlin, Germany. Temperatures across northern Europe are rising and in Germany a high of 36 degrees is forecast for the weekend. (Photo by Sean Gallup/Getty Images)