A woman takes part in a four-minute flash mob pillow fight at the Old Town Square in Prague, Czech Republic, December 22, 2016. (Photo by David W. Cerny/Reuters)

Swimmers in fancy costume take part in the New Year's Day swim at Saundersfoot in Wales, Britain, January 1, 2017. (Photo by Rebecca Naden/Reuters)

Drivers take part in a demolition derby organised by the Malta Motor Sports Association to raise funds for charity in Ta' Qali, outside Valletta, Malta, January 8, 2017. (Photo by Darrin Zammit Lupi/Reuters)

Mask dancers take part in a parade during the the International Festival of Masquerade Games “Surva” in the town of Pernik, some 30 km from Sofia, Bulgaria, January 31, 2016. (Photo by Vassil Donev/EPA)

Spanish legionnaires sing an anthem as they carry a statue of the Christ of Mena outside a church during a ceremony before they take part in the “Mena” brotherhood procession in Malaga, southern Spain, March 24, 2016. (Photo by Jon Nazca/Reuters)

Demonstrators take part in a protest aimed at showing London's solidarity with the European Union following the recent EU referendum, inTrafalgar Square, central London, Britain June 28, 2016. (Photo by Dylan Martinez/Reuters)

A Palestinian female masked militant from the Al-Quds Brigades, the military wing of the Islamic Jihad, takes part in an Islamic Jihad rally in Rafah, southern Gaza Strip, 29 July 2016. (Photo by Mohammed Saber/EPA)

A clown performs next to the Monument to the Revolution as he takes part in the Latin American Clown Convention in Mexico City, Mexico, October 21, 2015. The convention will be held from October 19 to 22 in Mexico City. (Photo by Henry Romero/Reuters)