People participate in 'No Pants Subway Ride'
Numerous people on Sunday participated in the annual 'No Pants Subway Ride' in places including  New York, London, and Boston. The aim of event is for participants to "experience something that's a little different than their average run-of-the-mill stuff". Organised by the Improv Everywhere comedy collective, the tradition was started as a prank in 2002 with seven participants.