THE BRONX – New unsettling video surfacing on Facebook shows three teenagers hopping on the back of a packed No. 4 train and holding on for their dear lives as it left a Bronx subway stop.

The stunt known as "subway surfing" happened on Tuesday around 4 p.m. inside the 149th Street- Grand Concourse Station.

Alexander Campos couldn't believe his eyes when he recorded the teens on his cellphone. A video that has been viewed close to a million times on Facebook.

"I'm like they're stupid," he said. "Why are they getting on the back of the train, they could fall off."

Campos shared the footage with PIX11 and spoke about the moments leading up to teens jumping on the train.

"We see a bunch of kids like trying to squeeze into the train and then they realize they can't fit in so instead of waiting for the next train to come they decide to get on the back of the train," Campos said.

Luis Rivera is a transit activist and knows these stunts are serious.

"Stop you're cheating death and you are only going to hurt yourself," Rivera said.

Rivera says its been an ongoing situation that's been getting worse since 2014.

In April 2014, a subway surfer was killed riding on top of a No. 6 train and in June 2015, a man appeared to hurt himself after he tried to leap between subway platforms and failed.

As far as Tuesday's incident, the MTA says they're taking a closer look at it.