The trial of Andrew Rossig, James Brady, and Marko Markovich, the men who parachuted off 1 WTC in 2013, began on Monday. The three daredevils are facing charges of burglary, reckless endangerment, and violating the city ordinance against BASE jumping. The outcome of their case could have important repercussions for all urban explorers in New York.

The jumpers do not dispute the fact that they jumped. They recorded the jumps with GoPro cameras, as seen above. But their attorneys argue that they didn’t recklessly endanger anyone, since they are highly experienced jumpers who “can land on a postage stamp,” and they took every safety precaution they could.

The burglary charge is the most serious one, since it’s a felony for which the jumpers could receive seven years in prison. Their attorneys are fighting that charge by arguing that since they jumped off the roof and not the interior of the building, the burglary charge is moot. Since they weren’t technically inside the building, they couldn’t have burglarized it. They also had no intent to steal anything.

They got inside the building by slipping through a hole in the fence, walking in the unlocked front door, and climbing the stairs to the roof. The tower was still under construction at the time, and James Brady was an ironworker on the site. The jumps raised questions about the security of the site, which is considered a prime target for terrorist attacks.