The No Pants Day, an international phenomenon, encourages people to travel in their undergarments.

It happens only once a year -- when they all dress up and step out of their homes, but sans their pants.

The No Pants on the Subway is an annual ritual where travellers take the tube without wearing pants and pretend like it's no big deal.

The event kick-started way back in 2002 in New York and has since caught the fancy of several countries including the UK.

Think we're joking? Take a look at these pictures!

Here's a picture from London underground.

Photograph: Paul Hackett/Reuters

Men and women flaunt their bare thighs in Vienna, Austria.

Photograph: Heinz-Peter Bader/Reuters

Meanwhile, in Berlin, a young couple showed off their goofy side.

Photograph: Hannibal Hanschke/Reuters

It's all in the family! In Berlin, here, a mother encourages her son to take part in the event.

Photograph: Hannibal Hanschke/Reuters

Now that's taking daring to an altogether different level! Don't you think so?

Photograph: Hannibal Hanschke/Reuters

New Yorkers join in to show their love!

Photograph: Stephanie Keith/Reuters

This is how London tubers stepped out on No Pants Day!

Would you dare to do this? Tell us!

Photograph: Paul Hackett/Reuters