The Titan II missiles were the largest, most destructive atomic weapons developed by the US. Stored at 54 underground missile silos located across the US, they were designed as a defensive response. Any single missile could wipe out a city the size of Los Angeles. With 54, armed and ready for launch together in less than 60 seconds, the goal was total annihilation of any enemy (primarily the USSR) that might choose to initiate an atomic attack against us. This “mutually assured destruction” (MAD) policy was designed to ensure that no one would ever undertake to attack us.
Operational in under 3 years from start of construction, and continuously ready until deactivation, these sites stood as retaliatory guardians for two decades. The START treaty between the US and USSR prompted the deactivation of all of these facilities. By agreement, only this one would be left intact as a museum and education facility. Other silos have been shut down and dismantled, and the sites sold for private use. In fact, one in Oro Valle, Arizona, now has a church on the site. So this is the only location in the world where a person can actually tour the last remaining one of these facilities.
The Titan II that is housed here is a real missile, but not the one previously armed here. It was the training unit, never fueled nor loaded with an atomic weapon. One and a half million people have done this guided tour since it opened, and we were absolutely “blown away” (figuratively speaking, of course) by what we saw and learned here. We would love to show this to our grandchildren and wish everyone had the opportunity to see this. Go if you can, but be sure to buy tickets ahead of time. The roughly 75 minute tour routinely sells out, and we saw at least several people get turned away on the afternoon when we went.
Building exterior. 
Their logo translates as “Custodians of Peace.” 
This sign in the educational waiting room and gift shop caught my eye. 
The tour takes you down 55 steps to the connecting tube between the control room on the left and the missile on the right. You are shown both, with excellent narration from professional guides, many of whom worked here. 
Here is the 1960 era control room. The missile was programmed for 3 possible sites. None of the actual targets have been released to this day. The launchers would never know. Took two people to launch, plus an elaborate system of fail safe controls. Note the giant spring on the upper left. These kept the room stable in the event of a nearby atomic blast. 
The missile was programmed to detonate either above ground for maximum area coverage, or on impact to destroy underground military facilities. 
The square hole in the payload portion was to demonstrate there was no warhead inside. Several test rockets were fired from California to a lagoon in the Marshall Islands. 87% were on target. We allowed the Russians to observe this. Why? We wanted them to know we were both willing and able to use it on whatever target we needed to hit.