In certain parts of the world, the ground is honeycombed with secret man-made tunnels and rooms. Many of these remain secret from the general public, some of them supposedly containing what amounts to a self-contained city, including electricity production, water purification, food storage, restaurants, and living quarters for thousands of people. Even some entire factories have been housed underground, to protect them from bombings during wartime. A number of the subterranean bases are World War 2 and Cold War relics, long abandoned by the governments which tunneled them out.

In 1967, Nick McCamley stumbled across such a complex in England. He was out bicycling with a friend in the wilderness when they unexpectedly came across a curious building in the middle of nowhere. It was standing in the middle of an open field, with no other structures evident for miles around. It had no windows and few doors, and it had strange black pipes leading from the sides of building into the ground around it. It appeared to be abandoned, and in disrepair.

Nick returned with another friend the following weekend to investigate further, and discovered that the main door was rotted and weak, so they coaxed it open and went inside. Because there were no windows, the interior was in complete darkness, so they lit their way with small make-shift paper torches. Inside, they followed a conveyor belt through rubber-flapped door which led to a steep slide that disappeared into the inky blackness below, their feeble paper torches unable to illuminate the slide’s other end. But they discovered too late that the slide was too steep and slippery to gain footing, and gravity got the better of them. About 100 feet down, they reached the bottom.

Short on matches and paper, and unaware of a way back out, the boys were a bit concerned. In the darkness, Nick groped along the wall to find his way, when his hand made purchase on some old electrical switches. He turned a few of them, and the lights jumped to life, revealing a corridor that stretched for about half a mile.

They spent the rest of the day exploring miles and miles of abandoned rooms and corridors. Everything worked… the lights all responded to their switches, the tunnels were air-conditioned, and the conveyor belts could be turned on (which saved the two chaps a lot of walking). There were railways which led off into long tunnels. But there was no sign that anyone had been there in years, it seemed utterly deserted.

It wasn’t until later that Nick McCamley learned where he and his friend had spent their day of adventure… a place called Monkton Farleigh. It has originally been a limestone mine, but during World War 2 it had been converted into an ammunition storage facility. Its tunnels were carved into about 200 acres worth of area, and it had its own electric plant. It was served by a network of railways, including (reportedly) a 160km stretch which connected to the heart of London. A couple of years before Nick and his friend had found it, it had been completely abandoned by the British Ministry of Defense. Nick ended up writing about his experience, and about other underground installations, in his book Secret Underground Cities.

Now, a few decades later, many more such underground facilities are coming into the public knowledge as each one’s existence is de-classified. Just recently, the British government put one such city up for sale, one with 60 miles of roads, it’s own railway station, a TV studio, its own telephone exchange, and a pub called the Rose and Crown. It was built in the late 1950s to house the Prime Minister and other government officials in the event of a nuclear attack from the Russians, and it still contains boxes of unopened 1950′s-era chairs, ashtrays, and tea sets. If you’re considering making an offer, its theoretical value is around £5 million (about $8.73 million in US dollars).

For something similar, but a bit more affordable, one might consider making a home in one of the United States’ retired Atlas missile silos. An unfinished silo, which comes with its own private airstrip, can be had for around $150 grand. Another $150k or so can make it a right comfortable home, which isn’t a bad deal considering these silos have the space of a mansion (15,000 square feet), excellent natural insulation (significantly reducing heating/cooling bills), and can withstand a one-megaton nuclear explosion a mile away. I want one.

There is good reason to believe that there are thousands of secret underground facilities around the world, and some of them are quite probably actively used today. However it is exceedingly difficult to research the topic, because most materials which discuss these facilities at any length immediately destroy their credibility by insisting that the tunnels are home to secret black-government conspirators, the Illuminati, extra terrestrials, Elvis, or some combination of the above.

But among the stories with at least a smidgen of credibility, there is evidence of US plans to build an underground airbase in World War 2, a secret city beneath Tokyo, a Cold War bunker in Canadawhich has been converted into a museum, and a Continuity-of-Government facility at Mount Weather in the US. Many others are described at abovetopsecret.com, though I put little confidence in their credibility, given their UFO-related claims.

No doubt there are hundreds of these underground installations both abandoned and in full operation; but being secret by definition, few can be reliably accounted for.