Just south of Tucson, Arizona, is the Titan Missile Museum, the only Titan ICBM silo you can tour.
For the full story, check out Apocalypse then: Inside the chilling Titan Missile Museum
Like when it was an active installation, you can't just wander onto the base.
Despite elaborate security measures, the military didn't foresee people on foot as much of a threat.
After buying your ticket, you head onto the base itself.
If you're able, the normal entrance is down a few dozen stairs.
There's a particular smell to military bases: steel, concrete and hydraulic fluid.
You can see several flights down through the grating.
While the security on the surface was OK, down here things get serious.
Multiple massive steel doors secure the facility. Or at least, they used to.
Now that is a serious door bolt.
There are two directions to go. One shorter passage goes to the Launch Control Center. The other goes to the missile.
The Launch Control Center is a slice out of time. Above here is the living quarters.
Want to launch an ICBM? There's a manual for that.
It's incredible to think what was possible with so little computing power.
This bank of instruments could be straight out of a retro sci-fi movie or a Fallout game.
Note the curve of the ceiling. This section of the facility is circular, with a domed ceiling for strength.
Fairly spartan living quarters for the four-man crew.
A normal-looking kitchen, except for the curved walls.
I wonder if Staff Sergeant Prievo has been back here.
Back down the corridor now, toward the missile.
Rocket fuel isn't exactly human-friendly.
The main corridor to the missile, allowing access and carrying the cables required to control and launch the missile.
Joints allowed flexing of the cableway in case of a nearby nuclear attack.
Not dramatic at all.
The missile! Well, the top part anyway.
Retractable platforms allowed access to every part of the missile.
Though 103 feet (31.4m) tall, the Titan II is only 10 feet (3m) wide.
Unlike its predecessor, the Titan II could be stored with its oxidizer fuel already onboard, so it could be ready to launch in under a minute.
The basic tour ends here, with views of the missile about two-thirds of the way up. The more advanced tours continue the exploration.
A tiny elevator drops us down to level 7, the base of the missile.
The base of a Titan II missile.
That's sunlight from the glass-covered viewing area.
The Stage 1 motors would have been here; you can see the platform cut out to fit around them and allow access. We'll see the Stage 1 engine later.
This is the view down, below the platform. It's a concrete wedge, forcing the rocket exhaust into two tunnels that channel it out and then up, parallel to the silo, and eventually out into the atmosphere.
I'm sure aesthetics weren't on the engineer's minds when designing this place, but how cool does this look?
There were multiple antennas, some permanently mounted on the surface, and others that would telescope up out of the ground in case the others were destroyed.
AN/TPS-9, or "tipsies" was a motion-sensing Doppler radar surveillance system.
The 760-ton (700 metric ton) silo door could be opened in 20 seconds. Now it is permanently half open to show that the silo has been decommissioned.
The open part of the silo is covered in glass, and it offers a unique view.
The LR-87 had twin motors, together creating 430,000 pounds of thrust (1,900 kN). It consumed 170 gallons (640 liters) of fuel per second.
This would have been hanging off the bottom of the missile, as seen in the earlier slide.
The reaction of the propellant and oxidizer is hypergolic, which means it ignites when combined without a spark. You wouldn't want to be standing here at the business end when that happens.
After the first stage ran out of fuel, it was jettisoned and the second stage, seen here, took over. It was less powerful, 100,000 pounds of thrust (445 kN), but burned for 15 percent longer, about 3 minutes. This pushed the Titan II to about 200 miles above the Earth.
Though it looks like it's in the middle of nowhere, Tucson is only about 20 minutes away and the town of Green Valley is right down the hill.
A better idea of scale. That's the nose cone/reentry vehicle. To the right, about the size of a refrigerator, is a scale model of the bomb.
For the full story, check out Apocalypse then: Inside the chilling Titan Missile Museum.