A dog dressed in a costume takes part in the Pet's Halloween Day parade at El Olivar Park in San Isidro, Lima, October 31, 2015. (Photo by Mariana Bazo/Reuters)

Palestinian girls take part in a ballet dancing course, run by the Al-Qattan Center for Children, in Gaza City November 25, 2015. (Photo by Suhaib Salem/Reuters)

People take part in the "Bison Race" winter extreme run competition in Zhodino, Belarus, December 5, 2015. (Photo by Vasily Fedosenko/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)

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)

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 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)