Rival supporters taunt each other after the FA Cup Third Round match between Manchester City and Manchester United at the Etihad Stadium on January 8, 2012 in Manchester, England. Localised clashes and stone throwing between fans took place on the streets after Manchester United beat Manchester City 3–2. (Photo by Christopher Furlong/Getty Images)

Visitors to Castle Combe take photographs in the village that was recently featured in Steven Spielberg's latest film, the wartime drama, War Horse, on January 10, 2012 near Chippenham, England. (Photo by Matt Cardy/Getty Images)

The Mount Bromo volcano erupts in the Bryce Canyon, Utah. (Photo by Reynold Dewantara/2016 National Geographic Travel Photographer of the Year Contest)

The hull on a boat that carried Rohingya migrants for three months is seen at Langkawi island, in the Malaysia's northern state of Kedah, Malaysia, May 12, 2015. Thailand and Malaysia may set up camps and detention centers to shelter hundreds of refugees arriving on their shores, officials said on Tuesday, as a leading inter-governmental agency said about 7,000 boat people were still adrift in the Bay of Bengal. (Photo by Olivia Harris/Reuters)

A People's Liberation Army (PLA) commando jumps through a fire hoop part of an exercise during an open day event at the Ngong Shuen Chau Barracks, the PLA navy base in the territory, in Hong Kong, China, 01 July 2015. Thousands of visitors attended the PLA open day yesterday and today to mark the 16th anniversary of the handover from British rule. (Photo by Jerome Favre/EPA)

An agent of the OIPR, one of the government agencies charged with managing protected land, stands next to cocoa trees inside Mont Peko National Park in Duekoue department, western Ivory Coast August 18, 2015. (Photo by Luc Gnago/Reuters)

A Mai-Mai rebel soldier shows off his guns at a checkpoint near the Mugunga refugee camp in Zaire; 1996. (Photo by Carol Guzy/The Washington Post)

Space shuttle Atlantis launches from pad 39A on July 8, 2011 at the NASA Kennedy Space Center in Cape Canaveral, Florida. The launch of Atlantis, STS-135, is the final flight of the shuttle program, a 12-day mission to the International Space Station. (Photo by Bill Ingalls/NASA via Getty Images)