A prisoner from the Pedrinhas prison is carried to receive medical help after he was injured during a fight between rival gangs inside the jail, in Sao Luiz, capital of Maranhao state, January 8, 2014. The recent posting on a major Brazilian news website of a video filmed last December 17 by Pedrinhas prisoners of the decapitated and tortured bodies of rival inmates inside the jail has highlighted some of the problems present in the country's prison system which houses nearly twice as many prisoners as its capacity, according to official statistics. (Photo by Douglas Cunha/Reuters/O Estado do Maranhão)

The British rock and roll group the Beatles talk to Ed Sullivan at CBS Studio 50 before their live television appearance on “The Ed Sullivan Show” in New York, February 10, 1964. From left to right are, Sullivan, John Lennon, Ringo Starr, holding a cigarette, and Paul McCartney. (Photo by AP Photo)

A tornado builds and travels southwest causing damage near Dean Rd. and 82nd Avenue in Hutchinson, Kan. on Monday, July 13, 2015. (Photo by Sandra J. Milburn/The Hutchinson News via AP Photo)

Student protestors, including one girl with a camera, struggle with soldiers from the Chinese Army, the PLA. Tiananmen Square, 1989. (Photo by Jeff Widener/Associated Press)

(L-R) Senior Drum Major Betts of the Scotts Guard, Bugler Lee Kidd, Guardsman Adam Deer of the Coldstream Guards and Lance corporal Michael Strong of the Princess of Wales's Royal Regiment pose in their full ceremonial attire at Wellington Barracks on March 21, 2012 in London, England. The group make up part of the ceremonial military personnel who will play a key role during Her Majesty the Queens Diamond Jubilee celebrations between June 2–5. (Photo by Dan Kitwood/Getty Images)

A performer dances at a housing exhibition in Wuhan, Hubei province, China, September 27, 2015. (Photo by Reuters/Stringer)

Delphina Bianchi, 10, sits on the bed of a truck carrying giant pumpkins from her grandfather's John Muller's farm at the Annual Safeway World Championship Pumpkin Weigh-Off Monday, October 12, 2015, in Half Moon Bay, Calif. (Photo by Marcio Jose Sanchez/AP Photo)

A model wears a creation by Peruvian designer Jessica Butrich during Lima Fashion Week, LIF Week Summer 15-16 in Lima October 28, 2015. (Photo by Mariana Bazo/Reuters)