It is hard to find any tangible evidence left of the Berlin Wall that was hastily built 46 years ago by Communist East Germany and torn down almost as quickly in 1989 in a rush to obliterate memories of the loathed barrier.

But Berlin has been re-discovering its painful Cold War past and putting the finishing touches on a $6 million bike trail that follows the path of the 160-kilometre wall built on August 13, 1961.

Tracing a "death strip" that ran next to the wall around the enclave of West Berlin, the "Berliner Mauerweg" (Berlin Wall Trail) is both a pleasant tour of the city's green belt and at the same time a surreal journey into its horrific history.

"The Wall is part of our past and we can't just erase it," said Michael Cramer, a Berlin political leader and mastermind behind the trail idea, that encountered years of resistance.

"The Wall Trail is there to help Berlin come to terms with the past. It's a reminder of not only of the division but also of how the Wall was peacefully swept away in 1989," said Mr Cramer, who is now a member of the European parliament for the Greens.

It is a fascinating bike tour that offers both a physical challenge and historical treats as it winds its way through mostly green sections of the city. There are about 30 signs posted along the route describing historical landmarks.

Some obstacles were created by newly reconnected roads and rail lines radiating out of West Berlin after the wall fell. A bike tunnel was built under one train line but other train lines force annoying detours into the city or countryside.

Dream houses have popped up on parts of the former death strip while horse stables and chicken farms are set up in other areas of reclaimed land, where menacing East German border guards and aggressive watchdogs once patrolled.

Birch trees have sprouted up and thick underbrush has spread across other areas of the strip, which was between five metres and about 100 metres wide - you can get lost if you miss one of the hundreds of grey "Mauerweg" signs set up at most intersections.

The Soviet-backed Warsaw Pact and the US-led forces during the Cold War squared off on either side of the 3.6-metre high Wall and "no-man's land" around West Berlin.

The Wall, which would have turned 46 yesterday, was built to stop a flood of East Germans to the West - some three million had left from 1949 to 1961. It became a symbol for a lack of freedom for East Germans.

Prosecutors said 270 died trying to get over, under it or through it by the time it was torn down. Some spots where famous killings took place are marked, including the final victim Chris Gueffroy. He was shot dead nine months before it was opened.

Some 3,200 people were arrested for trying to cross the border, jailed for "Republikflucht" (trying to flee).

The bike trail passes three remaining sections of the Wall remain that survived the hasty 1989 dismantling. They total less than two kilometres. Only five of the 303 guard towers are left.

Leaders in East and West wanted it demolished as fast as possible - to the chagrin of tourists and contemporary leaders who are now drafting plans to rebuild other parts for posterity.

"It's actually criminal that so much of the Wall was torn down and destroyed," said Mr Cramer, who began riding his bike along the Wall on the West side years before it collapsed. He wrote a book on the Wall trail and gives regular guided tours.

"There was too much Prussian efficiency in tearing it down." The initial resistance to his plans to preserve memories of the Wall with the bike trail melted away in the late 1990s. Erstwhile opponents - "Don't you have anything better to do than bike up and down the death strip?" - turned into supporters, as the city belatedly discovered the wall was probably its single biggest tourist attraction.

With the $6 million investment, the trail was improved in spots, marked, and new bike paths built in other areas from 2002 to last year.

There are still small sections being worked on and a battle over bike rights on one part is raging.

"It's all but finished now," said Mr Cramer, who has been struggling for almost 20 years to have the path built.

"One small park won't let cyclists ride through it but we're working on that."

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