A Houthi follower with fake blood on his clothes lies on the ground to represent a victim as others perform a war dance during a ceremony marking the first anniversary of the Houthi movement's takeover of Yemen's capital Sanaa September 21, 2015. (Photo by Khaled Abdullah/Reuters)

Festival goers having fun at the Balaton Sound music festival in Zamardi next to the Lake of Balaton, 110 km (68 miles) west of Budapest, July 8, 2017. (Photo by Sandor Csudai)

Street fighting in Berlin between Government troops and Spartacists, during the Spartacist uprising which followed Germany's defeat in World War I. (Photo by Keystone/Getty Images). 1919

A British policewoman chasing after a group of naked street boys by the Serpentine in Hyde Park, London. (Photo by Reg Speller/Getty Images). 1926

“José Doroteo Arango Arámbula (5 June 1878 – 20 July 1923) – better known by his pseudonym Francisco Villa or its hypocorism Pancho Villa – was one of the most prominent Mexican Revolutionary generals”. – Wikipedia

Photo: Mexican rebel leader Francisco “Pancho” Villa with one of the motorcycles used in the Battle of Torrero. (Photo by Topical Press Agency/Getty Images). August 1914

John Klatt and the Air National Guard MXS (right) and Mike Wiskus and the Lucas Oil Pitts take to the skies at the Memphis Airshow, on Sat., September 26, 2016 in Millington, Tenn. (Photo by Brandon Dill/Invision for John Klatt Airshows, Inc./AP Images)

People are seen on a street in Havana December 17, 2014. Stunned Cubans celebrated an apparent end to decades of conflict with the United States on Wednesday after both governments said they would restore diplomatic relations cut off in 1961. Many said they expected a restoration of ties would lead to the end of a U.S. economic embargo against Cuba, which is vilified daily in the official media and which Cubans accept as a key cause of widespread poverty on the island. (Photo by Reuters/Stringer)

Locals watch from the beach as waves hit an Indonesian tanker that ran aground near Narathiwat in southern Thailand December 19, 2014. The tanker loaded with palm oil, previously hijacked by its crew members and then seized by Thai authorities, was anchored some 400 meters from the beach but strong wind and waves broke it free, according to local media. (Photo by Surapan Boonthanom/Reuters)