If you didn’t know today was international  “Go Skateboarding Day,” you might have discovered that fact while rolling by Freedom Plaza earlier this afternoon.

U.S. Park Police dispatched officers to the downtown location to manage a large group of skateboarders who’d apparently gathered there to celebrate the occasion. Sergeant Anna Rose, a spokesperson for the Park Police, says between 200 and 300 skateboarders arrived at the plaza. Some threw small objects like soda cans at responding officers, she said.

“As backup arrived, that’s when the group started to disperse,” Rose added. “There were no injuries, no arrests, no property taken, nothing.” (She said similar incidents on NPS-controlled property have taken place in previous years.)

Skateboarding is not permitted in Freedom Plaza or on nearby sidewalks along Pennsylvania Avenue NW. On Twitter, witnesses described the situation with surprise:

https://twitter.com/mrpinkerton/status/745294571811278848https://twitter.com/bloomingdame/status/745300816714735616https://twitter.com/gregbilling/status/745301450318708736https://twitter.com/AmyBLeo/status/745303173502472193https://twitter.com/SegravesNBC4/status/745308980331814914https://twitter.com/HendWex/status/745309827912589317https://twitter.com/G00CHiE/status/745315762907324416

The International Association of Skateboarding Companies, which founded “Go Skateboarding Day” in 2004, encourages appreciators to “drop everything and skate” on its website. Today is the event’s 13th annual celebration.