On a cliff top above a small town in eastern Germany stands one of the most potent symbols of the Second World War. This grim l6th Century castle is Colditz, the most notorious prisoner of war camp in history. With its imposing walls and rigorous policing, Colditz was seen as the ultimate prison. The Germans believed escape from Colditz was aIl but impossible. However, over five extraordinary years, they were proved wrong time and again, defeated by achievements of boundless bravery, planning and ingenuity. Using archive material, dramatic reconstruction, and the personal testimony of Colditz veterans, this intriguing three part series from Channel 4 Television documents the creative and often spectacular attempt to go over, under or through the walls. For the first time the Allied Officers of three nations return to Colditz to reopen the tunnels and retrace the routes of their legendary escapes. With as many guards as prisoners, Colditz was considered escape-proof. But it wasn't long before the officers pooled their talents to create the greatest escape academy of the war. Often for the first time, the English, French, Dutch and Polish officers and their guards describe their experiences. Twelve years in the making, the film uses over 50 original interviews to capture the true stories behind the castle's infamous walls.