Some did it for love or because they were homesick. Others did it for various ideological reasons. Still more because they were drunk or had made a bet. Some came from West Berlin's main mental hospital in Spandau, unwisely situated next to the Wall.

Most of the men and women who climbed in the "wrong" direction were arrested and interrogated before being returned to the West. Some were imprisoned. Seven were shot to death by East German guards (though the communist authorities admitted to only two).

Footnote to history

Many of the cases seem even stranger when one realises that, from 1971, West Germans were allowed to cross legally into the GDR. Historian Martin Schaad researched this little-known aspect of cold war history for his book "Dann geh doch rüber“ - über die Mauer in den Osten". (The title refers to the favourite retort of West German conservatives to leftists who criticised the country's policies.)

Originally, Schaad considered the wall jumpers a mere odd footnote to history. Drunks, mostly, who must have acted on crazy impulse. Then he looked into the secret Stasi archives and realised there were hundreds of cases. "I was amazed how many of these stories there were, and how in many cases people had rational motives."

In 1988, just a year before the fall of the wall, there was a mass 'breakout'. On a small piece of territory still technically part of the east, anarchists and greens had set up camp. When West German police in full riot gear came to arrest them, 180 squatters fled over the Wall on ladders. They jumped down into the death strip, were loaded into trucks ... and were taken away to be given a hot breakfast before being sent home.

Many cases are simply sad. One of the most striking was that of "Berthold", a 17-year-old boy who fled to the West on impulse in 1974. "This guy has a big argument with his girlfriend, so he runs to West Berlin without any plan. The escape succeeds, but after three days it hits him: he'll never see the girlfriend or his parents again. So he re-climbs the wall and gets arrested. The Stasi make up a big story about him, saying he's a spy, and he goes to prison for three years. "

Jumping for the cause

In June 1970 a 27-year-old West Berlin department store worker called Heinz Müller got drunk, climbed one of the viewing platforms overlooking the wall to shout at the East German guards and fell asleep. Some time in the night he either fell or was pushed, and woke, disoriented, on the wrong side. When he started wandering around East German guards shot him dead.

One of the few ideologically-motivated jumpers was a West German communist called Werner Sibilski who didn't believe East German soldiers had orders to shoot, and climbed over the Wall from the West to prove the point. There were indeed no shots, but some Western newspapers claimed there had been. Enraged by this on his return to the West, Sibilski climbed the wall again. This time he was arrested and sentenced to a year and a half imprisonment in the GDR.

In the late 1980s, an American called John Runnings climbed the wall from West to East no fewer than 18 times as part of his idiosyncratic campaign for world peace. One stunt involved prancing along on top of the wall, taking swings at it with a sledgehammer. Another was a "pee-in", in which he ostentatiously urinated on what communist propaganda dubbed "the anti-fascist protective barrier."

"The Stasi really didn't want to arrest Runnings" says Schaad. "They saw him as a nuisance and tried to get the Americans to stop this mad guy breaching their border. But the Americans refused, saying 'there is no border in Berlin'. The dispute went on for years."

Mentally ill

The Stasi were frustrated because the West would never accept the Wall as an international border. They tended to see such incidents as examples of 'provocative disregard of the sovereignty of the GDR'.

Perhaps the most intriguing escapees from West to East were the mentally ill. "The Wall could look different to different people," Schaad explains. "If you're paranoid, if you think you're being followed and that someone is out to get you, then the Wall can come to seem exactly what East German propaganada says it is: a barrier for protection. Climbing from West to East becomes perfectly rational. Irrationally rational, as it were. "

"One guy climbed over three times. He didn't like being diagnosed as mentally ill, so, each time, the first thing he said to the guards was 'I want to see a doctor'. He just wanted a second opinion."