Watch your heads! Check out this video showing the American Queen, the largest steamboat ever built, passing under the Illinois Central Railroad Bridge in Cairo, Illinois while southbound on the Ohio River with only 6″ minimum clearance.

“We topped around above the bridge and backed down through it with the throttles ready to go ahead should anything go wrong,” a source told gCaptain. “We have several close bridges but that was the closest.”

Built in 1955 by McDermott Shipyards, the American Queen is an authentic recreation of a classic Mississippi paddle-wheeler and really is powered by a genuine steam plant. The vessel is currently operated by the American Queen Steamboat Company.