A reveller, covered in mud, chats with friends during the Glastonbury Festival at Worthy Farm in Somerset, Britain, June 26, 2015. The outdoor festival runs from 24 to 29 June. (Photo by Dylan Martinez/Reuters)

Nazi dictator Adolf Hitler greets supporters at a May Day gathering in the Olympic Stadium, Berlin. (Photo by Keystone). 1st May 1938

A woman uses the Aurasma app on an iPad which displays a virtual 3D animation of a Thundercat character which her colleague pretends to fight at the 2012 London Toy Fair at Olympia Exhibition Centre on January 24, 2012 in London, England. The annual fair, which is organised by the British Toy and Hobby Association, brings together toy manufacturers with retailers from around the world. (Photo by Oli Scarff/Getty Images)

Dressers make last minute adjustments to the costumes of dancers performing as horses during a press preview of American artist Nick Cave's first major work shown in Australia, entitled HEARD.SYD in Sydney, November 8, 2016. Over several days the live art performance will feature 30 “horses” dancing to live percussion beats in suits made from coloured raffia plant fibres. (Photo by Jason Reed/Reuters)

A biker rides in a “Ride for Pride” event to show support for the Confederate flag in Brandon, Hillsborough County, June 26, 2015. Several hundred people took part in the event. (Photo by Carlo Allegri/Reuters)

First graders attend a festive ceremony to mark the start of another school year in Slaviansk, September 1, 2014. September 1 marks the start of a new academic year for students in Ukraine. (Photo by Gleb Garanich/Reuters)

Monastic dormitories stand on the hillside at the Serthar Wuming Buddhist Study Institute on November 4, 2006 in Serthar County of Garze Tibetan Autonomous Prefecture, Sichuan Province, China. The Wuming Buddhist Study Institute is located in Larung Gar Monastery on an altitude of 3,700 meters (about 12,136 feet). The institute has the largest conglomeration of monks and nuns in Tibetan Areas, with over 40,000 monastics from the Tibet Buddhism Nyingma School, Gelug School, Sakya School and Kagyu School, including more than 10,000 nuns. (Photo by China Photos/Getty Images)

Dancers from the Philadelphia Ballet perform for Pope Francis (R) as he attends the Festival of Families rally in Philadelphia, Pennsylvania September 26, 2015. (Photo by Brian Snyder/Reuters)