It is still the hardest place to find. A glade down an overgrown path which seems like any other clearing in the endless woods of Brandenburg. But on its floor, there is a strip of concrete half the size of a tennis court, with a metal plate in the middle.

This is the launch-pad for a nuclear attack on Western Europe. Soviet nuclear missiles 20 times more powerful than Hiroshima were set up here, primed to be fired at targets including London and nuclear bases in eastern England.

Three years before the Cuban missile crisis, the Soviet Union had already placed nuclear weapons on foreign soil - in this wood, in what was then East Germany.

There was once a garrison town for 15,000 people here, but nature has overgrown this outpost of empire. When the Red Army left in 1994, the trees moved back to reclaim the land.

Only rough forest paths now lead to the complex itself, near the village of Vogelsang.

Image caption Birch trees now run rampant in the former garrison

In the 1950s, huge efforts were made to hide it from Western spies, both spy planes and those with prying eyes in the German population.

It may be partly because the first foreign Soviet nuclear base was so well hidden that no fuss was made. But intelligence agencies in West Germany, the US, the UK and France had a good idea what was going on.

At the heart of the ghost town remains an obelisk on which the silhouette of Lenin can be seen - just - at the pinnacle. There is a school, with peeling murals for children - swans flying and a sailing ship in bright blues and yellows. The upright figure of Lenin, and a mural of Red Army tanks in action, adorn the wall outside.

But the real business of the base lies at its other end - bunkers covered in sand for missiles and hardened concrete bunkers for warheads.

And then, down a short track, there is a clearing. This idyllic glade is where the weapons of mass destruction would have been launched.

From among the trees, the sky is barely visible - which means that the glade is barely visible from the prying spy planes of the 1960s. In this clearing among the oaks, there is a concrete platform, on which there is a metal plate for the rocket launcher to be bolted down for firing at targets up to 1,200km (750 miles) away.

London is at a distance of about 1,000km.

According to secret American intelligence reports released since the end of the Cold War, the base was set up in 1959. With Cuba, the aerial photographs were clear and the Soviet Union was confronted with incontrovertible evidence. After two weeks of tension, the Soviet Union backed down and agreed to remove the weapons.

Image caption Mobile launchers were anchored to metal plates in the concrete

But the rocket base in Germany was far less clear.

On August 11, 1960, the CIA wrote a secret report entitled "Possible Shyster Missile Base in East Germany". It is a series of observations that give a good idea of how disparate pieces of information add up to a clear and bigger picture.

The Americans knew there was a new missile and trailer system in use because it had been paraded before the Politburo and cameras on May Day in 1957 and 1960. The CIA dubbed it the Shyster or SS-3 (R-5 to the Russians).

But where would they deploy it? The Soviet Union was too distant for it to reach prime Western targets.

So pieces of a puzzle were filled in. Some of the details seem to have come from Western agents in East Germany who were simply watching what was going on - on the roads, or at railway crossings between Poland and East Germany.

"Shortly after midnight on the morning of the 20th of April 1959, a very slow moving column of Soviet military vehicles led by two GAZ-69A type trucks was observed proceeding from the direction in which the Jueterbog-Damm airfield and a railroad loading ramp are located in a northwesterly direction along the western outskirts of Jueterbog," the CIA report says.

A few months later, another observation was made: "A group of eight trailers probably identical to the Shyster parade trailer, based on analysis of available photography, was observed entering East Germany by rail at Frankfurt-Oder, on 9 September, 1959."

Khrushchev saw nuclear blackmail as a valuable policy initiative and he needed therefore, the nuclear missiles to back that up Dr Paul Maddrell, Loughborough University

A number of special military train shipments, suspected of carrying unidentified Soviet missiles and related equipment were also spotted at several other locations in East Germany during 1959.

From all of the clues, the CIA concluded that the site in the forest north of Berlin was to be used for mobile launchers of nuclear weapons.

"The use of Shyster missiles from bases in East Germany would strengthen the Soviet missile capability against many Nato targets in Western Europe and England," the report concluded.

A later CIA account told a story of the Soviet leader, Nikita Khrushchev, asking a military designer how many nuclear missiles it would take to destroy Britain and France. Before the designer could reply, the account continued, "Dmitri Ustinov, chairman of the Military-Industrial Commission, replied, 'Five. A few more for France - seven or nine, depending on the choice of targets.'"

Those missiles, it turns out, would have come from the glades in the forest north of Berlin. Research published in the US in 2001, suggests that there were two bases - Vogelsang and Fuerstenburg, 20km away - each with six missiles.

But it is also now known that the missiles deployed in East Germany in spring 1959, were suddenly withdrawn later in the year - unbeknownst to the CIA, which was still worrying about their presence in the country in early 1961.

Loughborough University's Dr Paul Maddrell, an expert on Western intelligence operations in East Germany, believes Khrushchev deployed the weapons as part of a policy of "nuclear blackmail".

Image caption A tank division was based at Vogelsang for decades

"He threatened in 1956, at the time of the Suez Crisis, to use nuclear weapons, and he very much regarded his threat as successful, so he saw nuclear blackmail as a valuable policy initiative and he needed, therefore, the nuclear missiles to back that up," he says.

And why were they so quickly withdrawn? Maddrell says it could be connected with Khrushchev's demand in November 1958 that Western countries should leave West Berlin. As Nato put in place plans to defend West Berlin - and if necessary to cross East German territory in order to relieve the encircled city - the threat of a full-scale war rose dramatically.

"It may be that in those very, very tense circumstances he [Khrushchev] didn't want nuclear missiles anywhere in the region," suggests Maddrell. "He didn't want a nuclear exchange."

For decades after that, Vogelsang was the headquarters of the Soviet Union's 25th Tank Division, the third biggest Soviet military base in East Germany.

Today it is a beautiful and eerie place. It is hard to believe that nuclear terror could have been unleashed from these woods.

When the Soviet soldiers left, they took virtually everything they could. Only a few loose photographs and posters are scattered around the derelict buildings. Pictures that couldn't be moved - like the painted portrait of Lenin on an outside wall or the murals in the school and canteen - remain, their paint flaking.

Nature is re-asserting itself, though even nature can't over-run a concrete nuclear bunker. And it will take time for it to completely over-run a whole town with a theatre, shops, offices, a gym and a school.

Slideshow production by Paul Kerley. Music courtesy of KPM Music.