President Trump said Sunday that he was ordering the FBI to reopen the Alcatraz Federal Penitentiary, the historic prison on an island off of San Francisco that has been closed since 1963.

“REBUILD, AND OPEN ALCATRAZ!” he wrote in a post on Truth Social. “When we were a more serious Nation, in times past, we did not hesitate to lock up the most dangerous criminals, and keep them far away from anyone they could harm,” Trump wrote in a post on Truth Social.

Once fortified with the goal of becoming the world’s most secure prisons, the government closed Alcatraz because it was too expensive to run — costing three times as much as most other federal prisons.

Inmates included notorious gangsters Al Capone and George “Machine Gun” Kelly, who had a history of prior escapes from prison. In 1962, three of Alcatraz’s prisoners escaped — John Anglin, his brother Clarence, and Frank Morris, who planted dummies in their beds and climbed out via rooftop ventilators.

As of 1972, Alcatraz has been owned by the National Park Service. The Golden Gate National Recreation Area, which manages the island, did not immediately respond to a request for comment.