By Richard Lister
BBC News, Washington state
I am standing at the doorway of an underground missile base in Washington state which once had the firepower of 600 attacks on Hiroshima.
The entrance is through a steel trapdoor a foot (30cm) thick, with concrete stairs descending five storeys into a gloomy labyrinth of tunnels and silos.
It still sends a shiver up the spine, even if the missiles are long gone and the bunker walls are now vivid with bright graffiti.
For those of us who remember the destruction of the Berlin Wall more clearly than the Cold War that preceded it, it is a chilling lesson in just how real the fear of nuclear annihilation was.
The Cold War warriors did not do things by halves. These Titan 1 missile bases took two-and-a-half years to build and were the most extensive, complex and costly ever constructed by the US Air Force that ran them.
Walking through the dusty base today, footsteps echoing eerily, you can still see why.
"Larson Site A" as this facility was known (Larson Air Force base had two other, three-missile complexes nearby) is one of only a very few of these early bases that is still intact and accessible.
It is essentially unchanged from when it was decommissioned and stripped in 1965. Built to withstand a nuclear blast as close as 1,000m away, every room was either mounted on springs or a cushioned floor to protect from vibration.
In the domed control room, there are still springs on the ceiling, from which the early computer equipment was once suspended.
Vast black tanks loom in side chambers. They held diesel fuel for the generators and drinking water for the staff of about 25 who lived underground for days at a time.
They would have been sealed in for weeks after a nuclear attack. The round surface air vents in the ceilings could be snapped shut at the flick of a switch. The escape tubes, sealed at the bottom by heavy iron lids, were filled with tons of gravel to slow the progress of any invasion force.
The atmosphere is cool down there, regardless of the temperature on the surface. The drab green and cream paint is peeling in places; pipes and vents snake everywhere.
Just weeks after it became operational, President John F Kennedy put the Larson base and the rest of his armed forces on "Defcon 2" (defence readiness condition 2), one step below maximum readiness and the only time such an order was ever made.
The base is up for sale for $1.5m - an ideal home or summer camp?
It was October 1962 and US spy planes had spotted Soviet missile bases in Cuba.
For two weeks the world hovered near the brink of a nuclear conflict. Those in the missile bases waited for the order to turn the two launch keys, which would result in the death of millions of people.
It never came. But the last base commander, Colonel Clyde D Owen, told me they were constantly aware of just how much destructive power they had.
He said he would never forget the first time he was brought through the tunnels to see a giant Titan missile in its silo, describing it as "an awesome sight".
In the end, the first generation of Titans proved so difficult to keep operational that all 18 Titan 1 bases were scrapped just three years after they were finished.
Eventually, hundreds more silos would be built, scattered across America's quiet backwaters.
Most of those from the Cold War era are now gone. They have been replaced by newer missile technology or decommissioned under treaties with the Soviets.
Some of these underground warrens are now owned by water companies and storage firms. Others have been turned into homes.
Of the rest, many were abandoned with their silo doors open and have slowly filled with water, prompting illegal night-time visits by extreme scuba divers.
Bari Hotchkiss, who is selling Larson Site A on internet auction site eBay, says he has been approached by a company interested in turning one of the 160-foot missile silos into an artificial reef.
An entrepreneur and amateur historian, he bought the complex on a whim in 1998. Ideally, he would like to see it turned into a children's summer camp and educational facility.
It is an admirable aim - though for the moment the base still feels haunted by the ghosts of Armageddon.