It was immortalised by the film The Great Escape - now a group of men have revealed the miracles behind the Stalag Luft breakout by recreating the famous tunnels.
Since the 1963 movie starring Steve McQueen and Richard Attenborough, the escape of RAF airmen from the German prisoner of war camp has become the stuff of legend. But many of the secrets of how 76 men escaped via a 100m-long tunnel from Stalag Luft III, a camp built especially to thwart an escape by such means, has remained.
A team of experts, archaeologists, veterans and modern-day RAF personnel led by Cambridge University's Dr Hugh Hunt returned to the site near Zagan, Poland, to find out.
They excavated for the first time the remains of "George", a tunnel that was in progress when the war ended, and the famous "Harry" tunnel from which the Allied airmen escaped on March 24, 1944.
Dr Hunt said: "Although only a handful of men worked on the tunnel directly, the escape plan involved hundreds of prisoners who never really knew what the plan actually was. It was some people's job to move bin lids or wear their hat a certain way if a German guard was coming - but they never knew why.
"It took a year to dig the tunnel but for more than 70 years since then, 'Harry' and 'George' have remained undisturbed - and with them the final secrets of a remarkable story and history. We all came away with an appreciation of just how difficult - and dangerous - digging the tunnel must have been."
The modern day team designed a 10m tunnel, evaluated shoring methods, built the railway track and crafted digging tools and saws fashioned from bits of gramophone players, bunk beds and kit bags.
To make the real great escape, the prisoners led by Squadron Leader Roger Bushell, stole 4,000 bed boards, 90 double bunk beds, 635 mattresses, 3,424 towels, thousands of knives, forks and spoons and around 1,400 Klim powdered milk cans - used to engineer an ingenious ventilation system.
Dr Hunt said: "It's simply amazing what they achieved given how difficult it was. But talking to some of the people who were involved, we also got a sense of the bravery, camaraderie and fun of it all."
The results can be seen in Digging the Great Escape, shown on Channel 4 at 9pm on Monday.