A terror plot focusing on the Brooklyn Bridge was revealed in 2003, but documents newly released by WikiLeaks show that earlier warnings might've increased security and foiled the plot. Prior to September 11, 2001, the documents reveal, a terrorist training camp in Afghanistan was teaching methods to bring down bridges. After 9/11, Khalid Sheikh Mohammed instructed an operative to "destroy the Brooklyn Bridge by cutting the suspension cables," according to one of the documents obtained by the New York Times.
Since 9/11, the Brooklyn Bridge has been very carefully guarded, adding security cameras, police cars, and a police boat. Despite those precautions, the police commissioner admits there was a vulnerability, discovered after the operative was arrested in 2003: a room where it would be possible to cut or weaken some of the thinner cables. The plot, though it seemed far-fetched, "was doable," he said. Ultimately, however, the operative was believed to have been deterred by the post-9/11 security measures in place.