When it comes to riding the subway, New Yorkers have seen it all. In fact, encountering someone pants-less on the subway seems almost like a right of passage.

But when more than 1,000 straphangers strip down to their skivvies at the same time, even the most oblivious New Yorker has got to know something is up – right?

Enter the No Pants Subway Ride. What started as a prank by seven guys in New York City in 2002 has grown into a quirky tradition that has spread to dozens of cities around the world.

Organized by Improv Everywhere, the No Pants Subway Ride invites people to have a little fun by ditching their pants (but keeping their underwear), hopping on a train and pretending like it’s just another day in New York City.

The key to the prank is that Improv Everywhere asks participants not to explain what’s going on to those who don't know – just get on the train and act as if it’s business as usual.

Now in its 16th year, more than 30 cities are participating in the 2017 No Pants Subway Ride. Here’s how you can take part, too:

Date: Sunday, Jan. 8, 2017

Time: 3 p.m.

Wear: Normal clothes (jacket, hat, gloves, etc.)

Bring: A MetroCard and a bag or backpack to keep your pants in.

Where: There are seven meeting points spread across Manhattan, Brooklyn and Queens. Each meeting point has its own route.

Astoria: Meet at Hoyt Playground

Flushing Meadows Park: Meet at the Unisphere

Gowanus-Park Slope: Meet by the Old Stone House

Williamsburg-Bushwick: Meet at Maria Hernandez Park

Downtown Manhattan: Meet at Foley Square

Midtown Manhattan: Meet at Hudson Yards Park on 34th Street

Uptown Manhattan: Meet at the Great Hill in Central Park

What's next: Participants at the meeting points are organized into groups and assigned specific train cars. Once the groups split up, act like you don’t know each other and go about your day as if you were actually still wearing pants (nothing to see here, folks). You can find out more details by heading to improveverywhere.com/2017.