What was accidentally found under the Brooklyn Bridge during a routine check?

A bomb shelter was discovered accidentally in 2006 by city workers doing a routine check on the Brooklyn Bridge.

Previously, the city hadn’t revealed the location for security reasons. The bomb shelter is one of many secret rooms in the bridge. On the Brooklyn side is the Brooklyn Bridge Anchorage, a series of eight rooms framed by the bridge’s piers. Designed by the bridge’s architect John Roebling in the Gothic style, the 50-foot-tall space was planned to host a shopping arcade, which never panned out. The rooms were used as municipal storage and for an occasional art exhibition until closing in 2001 for security reasons.