Normally, New Yorkers have to wait until the No Pants Subway Ride or the World Naked Bike Ride to see fellow NYers in their skivvies—it's not like we live in a city where one can just walk outside and be greeted by people in underoos, doncha know. But twas so Friday evening in Central Park, as hundreds of New Yorkers stripped to their pantaloons for the annual Underwear Run.

The Naked Cowboy, Robert Burck, was the enthusiastic grand marshal as around 500 triathletes participated in the 1.7-mile run, which kicked off New York City Triathlon weekend. More than 4,000 runners are expected to take part in the real Triathalon, which takes place this Sunday.

Whether or not they wear their superhero-emblazoned underwear is up to them—but they certainly came out in droves yesterday, as you can see in the photos above. Photographer Sai Mokhtari said the short race was a reminder of everything good about NYC: "I kept finding myself thinking, I LOVE THIS FUCKING CITY!!! The fun, the irreverence, acceptance, confidence and diversity of the crowd..! NO other city gives it to you like this."