Notice anything unusual on your Sunday commute? Thousands of people around the globe public rode transit without wearing any pants (trousers).

Transit riders in Berlin took their pants off on Sunday.

Transit riders in Berlin took their pants off on Sunday. Image by YouTube Newswire

Those people were celebrating the annual No Pants Subway Ride, which was started in 2002 by the comedy group Improv Everywhere in New York. The event is marked by people getting onto trains wearing all their winter gear, but only their underwear on the bottom.

According to Improv Everywhere, the event started as a small prank and “has grown into an international celebration of silliness”. They explain that the goal is that people randomly board the subway at different stops without wearing pants and behave as though they do not know each other.

People participated from Moscow to Jerusalem, according to Improv Everywhere’s website.

Watch video of the event here and here.