A Palestinian reveller takes part in a colours festival organized by Palestinian activists in the West Bank city of Ramallah August 20, 2015. The festival is inspired by the Hindu spring festival of Holi. (Photo by Mohamad Torokman/Reuters)

Revellers take part in the Holi Party Festival at the Niemeyer Center in Aviles, northern Spain, August 29, 2015. The event is inspired by the Hindu Holi spring festival of colour celebrated mostly in India but has recently spread to other countries. (Photo by Eloy Alonso/Reuters)

Troops of the Interior Ministry take part in a parade during a ceremony marking the Iraqi Police Day at a police academy in Baghdad January 9, 2016. (Photo by Khalid al Mousily/Reuters)

Participants take part in the annual Great Spitalfields Pancake Race in aid of London's Air Ambulance in London, Britain February 9, 2016. (Photo by Stefan Wermuth/Reuters)

A participant takes part in a zombie parade during the Brussels International Fantastic Film Festival in Brussels, Belgium, April 9, 2016. (Photo by Yves Herman/Reuters)

A niqab-wearing Salafist protester takes a selfie as she attends a demonstration against the ban on the sale and manufacturing of the full-burqa in Rabat January 15, 2017. (Photo by Reuters/Stringer)

The snitch runner takes the broom from between the legs of a Werewolves of London quidditch player during the Crumpet Cup quidditch tournament on Clapham Common on February 18, 2017 in London, England. (Photo by Jack Taylor/Getty Images)

Couples take part in a competition during a mass wedding of 64 doctoral student couples at Harbin Institute of Technology, a university in Harbin, Heilongjiang province, China, June 4, 2017. (Photo by Reuters/Stringer)