LONDON, ENGLAND - APRIL 06: Revellers take part in a giant pillow fight in Trafalgar Square on 'International Pillow Fight Day' on April 6, 2013 in London, England. Mass public pillow fights have been arranged in numerous cities around the world as part of the 'Urban Playground Movement' which facilitate free, public non-commercial events. (Photo by Oli Scarff/Getty Images)