A Yemeni soldier, pictured through a vehicle's windscreen, which was damaged by a bullet, gestures out of the window, in Marib, Yemen October 15, 2015. Marib is a city that is heavily armed even by the standards of Yemen, where the ready availability of weapons helped start civil war and is now preventing anyone coming out on top. Yemenis often say there are three guns for every person, a boast that has become an urgent concern in a country where the United Nations says the humanitarian situation is "critical". (Photo by Angus McDowall/Reuters)

A lighting bolt flashes in the sky as U.S. Army M1A1 Abram tanks roll through the desert December 9, 2002 near the Iraqi border in Kuwait. (Photo by Joe Raedle/Getty Images)

1974: American boxer Muhammad Ali, formerly Cassius Clay, strikes an aggressive pose at a press conference on November 29, 1974. (Photo by Harry Dempster/Express/Getty Images); American actor Will Smith at the Royal Premiere of the film Ali in London on December 11, 2001. Smith starred as Muhammad Ali in the film. (Photo by Dave Hogan/Getty Images)

A young man “painting” the Eiffel Tower. (Photo by Keystone/Getty Images). 9th May 1970

A shoebill is displayed at Ueno Zoo in Tokyo August 28, 2012. (Photo by Itsuo Inouye/Associated Press)

Melissa March, 13, is seen backstage during the Cuban Otaku festival in Havana, Cuba, July 24, 2016. (Photo by Alexandre Meneghini/Reuters)

Comedians and cast members from the Pleasance's 2016 programme bounce on yellow spacehoppers in costume at Calton Hill on August 15, 2016 in Edinburgh, Scotland. The Pleasance and Waverley Care are marking a twenty five years in partnership, it's a unique relationship that helps raise awareness and challenges the stigma that continues to be attached to HIV and Hepatitis C and has raised more than £375,000 so far. (Photo by Jeff J. Mitchell/Getty Images)

A woman eats candy in the shape of a phallus during the Kanamara Matsuri, or Iron Phallus Festival through a street near the Kanamara shrine in Kawasaki outside of Tokyo April 5, 2015. The festival celebrates fertility and is used to raise awareness and money for the prevention of sexually transmitted diseases. (Photo by Thomas Peter/Reuters)