Nike Missile Site SF88L
Base SF-88 is one of only a few preserved Nike Missile Bases -- between 1953 and 1979, 280 of these bases formed protective rings around major US cities to defend against nuclear bomber attacks.
The National Parks Service runs free tours every half hour while open, taking visitors back to the Cold War. They flip on the rotating radar unit, lead a stroll through the Testing and Assembly building, and end up taking tour groups via elevator to the underground storage area.
SF-88 is on some of the most beautiful and valuable real estate of any missile base, so it's a small wonder it has been saved (The NPS maintains another declawed Nike Base on the East Coast, on NJ's Sandy Hook).
Though no longer launch-ready, volunteers continue to repair and spruce up the facility so that future generations won't forget the Nike Missile Program.