Group seen jumping barrier at top of Vernal Falls in Yosemite National Park

YOSEMITE NATIONAL PARK, Calif. -- Here's something you should never attempt.

A video is making the rounds online showing a group of visitors at Yosemite National Park after they jumped a barrier at the top of Vernal Falls.

One of them is seen posing for a photo at the edge of the 317-foot drop.

The National Park Service warns people not to cross the railings to prevent tragic consequences.