White House to Treasury Building tunnel, Underground passage between White House and Treasury Building in Washington, D.C., United States.

The tunnel connects the East Wing basement of the White House to the Treasury Building following a zig-zag pattern designed for protection. Inside, modern security systems include cameras, alarms, and specialized locks throughout the passage.

Construction began in 1941 following the Pearl Harbor attack to create a secure escape route. The project was part of early wartime measures to strengthen government protection.

The passage shows how government buildings were designed during wartime to keep daily work running without interruption. Its construction reflects technical advances that combined security needs with practical government operations.

The tunnel is closed to the public and guarded by the Secret Service, with cameras, alarms and cipher locks along its length. It cannot be seen on official tours; the Treasury Building's exterior and the areaway it connects to are the only parts visible from outside. The passage runs beneath the street between the East Wing and the Treasury.

The tunnel is not straight: it zig-zags under the street to lessen the concussion of a direct bomb hit, and small rooms along its 761 feet once held cots so it could serve as a shelter. It is guarded by the Secret Service with cameras, alarms and cipher locks.