The Royal Air Force aerobatic team, the Red Arrows, perform during The Royal International Air Tattoo at the RAF in Fairford July 11, 2014. (Photo by Stefan Wermuth/Reuters)

Police clash with “Occupy Melbourne” protestors on October 21, 2011 in Melbourne, Australia. Protesters and riot police clashed in Melbourne today after police, acting on a Melbourne City Council eviction order, attempted to break up the crowd of hundreds that had been positioned in City Square for a week. (Photo by Mark Dadswell/Getty Images)

Kurdish gunmen hold their rifles in front of the burning house of a Shi'ite militiaman during clashes in Tuz Khurmato, Iraq, April 24, 2016. (Photo by Goran Tomasevic/Reuters)

A woman cries after riot police dispersed demonstrators during protests to oust Narok county Governor Samuel Tunai in Narok, Kenya, January 26, 2015. At least seven people were injured on Monday in clashes between Kenyan police and protesters from the Maasai ethnic group who accuse a local governor of corrupt handling of tourism funds from the Maasai Mara game reserve, the Kenya Red Cross said. (Photo by Thomas Mukoya/Reuters)

An anti-government demonstrator argues with a Bolivarian National Police officer during a march toward the headquarters of the national electoral body, CNE, in Caracas, Venezuela, Wednesday, May 18, 2016. Opposition protesters were blocked from reaching the CNE as they demand the government allow it to pursue a recall referendum against Venezuela's President Nicolas Maduro. (Photo by Fernando Llano/AP Photo)

Corporal of Horse Andy Radford prepares to mount his horse in the parade square at Hyde Park Barracks on April 15, 2011 in London, England. Members of the Household Cavalry gave a behind the scenes tour of many of the duties performed as part of their daily routine, including special preparation ahead of the forthcoming Royal Wedding. The Household Cavalry will perform several ceremonial duties during the summer, including the Royal Wedding on April 29, and the Queen's Birthday Parade (Trooping the Colour) in June. (Photo by Dan Kitwood/Getty Images)

Police officers carry an opposition activist, who was detained while taking part in an unauthorized rally, at the Triumfalnaya Square in central Moscow, late on December 6, 2011.

Photo by: Sergey Muhamedov; Source: LiveJournal

Bunting hangs on Regent Street on April 19, 2011 in London, England. Preparations are underway across the city as the Royal wedding of HRH Prince William and Kate Middleton draws nearer. (Photo by Dan Kitwood/Getty Images)