Revellers take part in the annual “Naval Battle” of Vallecas in Madrid, Spain July 19, 2015. The slogan for this year's water battle is “Get wet for Alfon, freedom for Alfon”, referring to Alfonso Fernandez Ortega, a Vallecas resident who was sentenced to four years in prison in June. The festival was started spontaneously in 1981 when some neighbours started to throw water at one another due to high temperatures during the Virgen del Carmen Festival. (Photo by Juan Medina/Reuters)

A petitioner with her grievances written on her clothes walks along a street in Beijing Tuesday, December 22, 2015. After months behind bars, Pu Zhiqiang, one of China's most prominent human rights lawyers, left a detention center Tuesday after receiving a suspended prison sentence in a case involving online comments critical of the ruling Communist Party. (Photo by Ng Han Guan/AP Photo)

In this photo taken June 3, 2009, a female North Korean soldier looks out from behind a barbed-wire fence around a camp on the North Korean river banks across from Hekou, northeastern China's Liaoning province. North Korea's top court has convicted two U.S. journalists, and sentenced them to 12 years in labor prison, the country's state news agency reported Monday. (Photo by Ng Han Guan/AP Photo)

Workers attach a hat to a pinata depicting the drug lord Joaquin “El Chapo” Guzman at a workshop in Reynosa, July 21, 2015. Guzman broke out of Mexico's top maximum security prison through a tunnel built into his cell earlier this month. (Photo by Daniel Becerril/Reuters)

Playboy Bunnies pose for a selfie at the premiere of “The Transporter Refueled” at Playboy Mansion in Los Angeles, California August 25, 2015. The movie opens in the U.S. on September 4. (Photo by Mario Anzuoni/Reuters)

Unforgiving temperatures of up to 60℃ (140℉) beat down on these saltminers on a daily basis. The mines, situated in the Afar Triangle in Ethiopia, stretch across 38,000 sq miles and at their lowest point are more than 300ft below sea level. Joel Santos travelled to capture the area’s dry, brutal beauty. Here: Dromedaries and donkeys are used to transport the salt. (Photo by Joel Santos/Barcroft Images)

Fighters of the pro-government Popular Resistance Committees militia carry a cannon as they transport it in parts to Yemen's southwestern war-torn city of Taiz December 26, 2015. (Photo by Reuters/Stringer)

The space shuttle Endeavour is transported to the California Science Center in Exposition Park from Los Angeles International Airport (LAX) in Los Angeles, California. (Photo by Kevork Djansezian)