Participants climb over a wall at the “Tough Mudder” endurance event series in Arnsberg September 6, 2014. Competitors who took part in the endurance event saw themselves having to overcome various military style obstacles. (Photo by Ina Fassbender/Reuters)

Damai, 3 years old Bornean orang utan plays courtyard at Surabaya Zoo as he prepares to be released into the wild on May 19, 2014 in Surabaya, Indonesia. The two baby orangutans, brothers, were found in Kutai National Park in a critical condition having been abandoned by their mother on May 14, 2014. The Centre for Orangutan Protection (COP) have since been nursing the animals back to health, treating them for malnourishment and 16 wounds predominantly to the feet and hands. (Photo by Robertus Pudyanto/Getty Images)

A six-year-old acrobat performs on the opening of a tourist festival in Bozhou, Anhui province, China May 3, 2015. (Photo by Reuters/China Daily)

A Thai policeman patrols around a bar area in central Bangkok, Thailand, August 19, 2015. Thai police on Wednesday issued an arrest warrant for an individual they described as a “foreign man”, in connection with a bomb blast in Bangkok that killed 20 people, including many foreigners. (Photo by Kerek Wongsa/Reuters)

A man from Dinka tribe holds his AK-47 rifle in front of cows in a Dinka cattle herders camp near Rumbek, capital of the Lakes State in central South Sudan December 14, 2013. (Photo by Goran Tomasevic/Reuters)

Alfred Hitchcock (1899 – 1980) in front of a caricature of his profile at a press reception in London for his new film “Frenzy”. (Photo by Central Press/Getty Images). 24th May 1972

An F/A-18 Hornet assigned to Strike Fighter Squadron One Five One (VFA-151) emerges from a cloud created when it broke the sound barrier in the skies over the Pacific Ocean, July 7, 1999. (Photo by John Gay/US Navy)

A British policewoman chasing after a group of naked street boys by the Serpentine in Hyde Park, London. (Photo by Reg Speller/Getty Images). 1926