Since it launched eight years ago, No Pants Day has attracted increasing numbers of trouser-less citizens around the world. On Saturday around 3,000 people stripped off for a special "no pants" social experiment on the New York subway.

The yearly "No Pants day" itself takes place on the first Friday of May. This year it seems they couldn't wait to get undressed, so set up a special "No Pants Day Subway Ride", inviting public transport users around the world to take off their pants on Jan. 9. New York saw the highest number of trouser-less travellers, with 3,000 of them infiltrating the subway.

No Pants Day, illustrated


Photos posted by Flickr users Katie Sokoler and Brian Foutain.

“This year we had rides in 44 cities in 16 countries”

Charlie Todd is a member of Improv Everywhere, the flash mob group that organises the gatherings.

The first time we did this in 2002, there were only seven of us, mostly men. The rule was to not talk amongst ourselves, and if someone asked - we'd simply forgotten our pants. In 2006, the event was interrupted by the police. An NYPD officer arrested all the participants and made them get off the train. Eight of them were handcuffed and charged, but the judge let them off - it's not actually illegal to go out without any pants in New York!

For Saturday's event, which was the ninth edition, all the participants, so 3,000 people, were informed on the net. They met up in several places in the city and then took the metro before coming back to Union Square. People found it pretty funny. My favourite reaction was one man who loudly yelled, ‘What the cuckoo is going on?'  (which is not a common phrase in English.)

I've worn the same pair of orange and white polka-dotted boxers for the last several years.  I actually only wear them once a year now!  I think they're funny in a classic way.

I think it's fabulous that No Pants has spread to new cities and countries. This year we had rides in 44 cities in 16 countries, including the cities of Zurich, Amsterdam, Boston, Buenos Aires..."