BATON ROUGE - A century-old tunnel hidden beneath the streets of downtown Baton Rouge is being brought back to life.

The Tunnel is a new speakeasy set to open in an underground room below the Hilton Hotel on Convention Street. Access is limited and guests will only be able to enter if they find a hidden key inside of the hotel by using clues from social media.

"They are going to need a special key to enter, and they are going to have instructions with that key on where to enter from," said Leslie Thompson, Director of Sales and Marketing for the Hilton Hotel Baton Rouge Capitol Center. "And they will need to have that key to continue the experience."

It's a mystery with decades of history behind it. The Hilton Hotel, once called the Heidelberg, was one place Huey P. Long called home. 

"He spent an amazing amount of time at this hotel," Thompson said.  "A lot of business was conducted."

The former governor often utilized the underground tunnel that connected the Heidelberg to the King Hotel, now called the Indigo, as a pathway to reach his mistress without being spotted by the press. Other high-profile guests such as Al Capone traveled through the tunnel as well, according to Thompson. 

"We know there was a lot of those characters that stayed in our hotel, so I'm sure they were in this very space," Thompson said. 

The hunt for hints doesn't stop once guests enter the speakeasy. Thompson says guests can discover clues inside of The Tunnel that can be exchanged for special drinks and other prizes. 

For more information about when The Tunnel will open, you can follow their Instagram or subscribe to the speakeasy's newsletter.