The FBI posted pictures of the narrow underground tunnel leading to a branch of Chase Bank in Pembroke Pines, about 20 miles (32 kilometers) north of Miami.
Police and the FBI were called in Tuesday night after the road workers realized that a manhole-sized hole in the road was caused by a tunnel.
Further digging revealed a crude 50-yard (46-meter) tunnel leading from a wooded area to the bank on S Flamingo Road.
The tunnel was just wide enough for a single person to crawl through on their stomach.
“I would like to say I’ve seen something like this in movies,” FBI agent Mike Leverock told reporters. “However, this hole is so small. It’s unique.”
The FBI said in a tweet that it was treating the case as an “attempted bank burglary.”