A high-flying stunt in Vancouver’s Stanley Park was the cause of both excitement and controversy on Tuesday.

A video shows a group of thrill-seekers slacklining several feet off the ground from a Stanley Park cliff to Siwash Rock, one of the city’s landmarks.

“You’ve got North Vancouver in the back and you’re looking out over English Bay,” Adam Mertens, one of the slackliners, told CTV Vancouver. “It’s pretty spectacular scenery.”

Slacklining is a sport that has been growing in popularity over the last few years. Similar to tight-roping, it involves walking across a strip of nylon webbing anchored between two points. The line is often more flexible that a tightrope.

The display of daredevilry only lasted half an hour, but the Vancouver Board of Parks and Recreation was quick to speak out against the activity.

“I’m not happy,” said board general manager Malcolm Bromley. “When it crosses a line and endangers public safety or disrespects a really important cultural place like Siwash Rock, that really raises a lot of concerns for me.”

Technically, the stunt violated park rules because of the no trespassing sign posted next to Siwash Rock.

The park board hasn’t ruled out fines, but the slackliners have promised to not repeat the stunt.

With a report from CTV Vancouver