REPORTER: New York City subway riders got more than they bargained for when some commuters boarded trains missing one critical clothing item - pants. It's the middle of winter, but thousands of participants in the No Pants Subway Ride annual hoax had no problem shedding their trousers for some serious shock factor. It certainly surprised Barbara Hill who has lived in New York her whole life.
BARBARA HILL, NEW YORK RESIDENT: "Shocking. Oh my God. I mean, I've seen weird stuff, but not like this."
REPORTER: And riders like Ryan McDonald seemed a bit grossed out.
RYAN MCDONALD, SUBWAY RIDER: "The first thing that comes to mind is that's a little dirty, especially if you sit down on the subway without any pants on."
REPORTER: But participant Jennifer Melara said the goal is to lighten the mood.
JENNIFER MELARA: "It's a great feeling. It's not just great for us, but it's great to, you know, like, kind of get everyone else laughing in this time of sorrow and despair and everything else that's crumbling around the world. It's a little happiness in the day."
REPORTER: Mexico was one of 25 countries that took part in the annual event. Proof that there are people all over the world, who love a good prank.
In Britain, pants (or underpants) are what you wear under your trousers. So if you went pantless on the London underground, it's unlikely that anyone would notice.