At this original Titan II missile site, a crew stood ready 24/7 to launch a nuclear warhead within seconds of receiving a presidential order. The Titan II was the first liquid-propelled intercontinental ballistic missile (ICBM) that could be fired from below ground and could reach its target – up to halfway around the world – in 30 minutes or less. Active from 1963 to 1986, this is the only one of 54 Titan II missile sites nationwide to be preserved as a museum.

The 75-minute tours, usually led by retired military types, are both frightening and fascinating. After descending 35ft and walking through several 3-ton blast doors, you enter the control room where you experience a simulated launch before seeing the actual (deactivated, of course) 103ft-tall missile still in its launch duct. The tour is wheelchair accessible and reservations are essential. Exhibits in the small museum trace the history of the Cold War and related topics.

The museum is 24 miles south of Tucson, off I-19, exit 69.