Colditz Castle sits on a rocky spur above a river in Saxony, and its story begins in 1046, when Emperor Henry III allowed a settlement on the hill. It was burned by the Hussites in 1430, burned again in 1504 when a baker accidentally set it alight, and rebuilt as a Renaissance residence and hunting lodge. Over the centuries it held one of the largest zoos in Europe, grew to 700 rooms, and then declined into a workhouse, a mental hospital from 1829, and a sanatorium where 912 patients died of malnutrition during the First World War.

This episode follows the castle to its most famous role. In 1939 it became Oflag IV-C, a high security camp for Allied officers, and the Germans filled it with men who had already escaped from other camps, trusting the cliffs, the 90 foot walls, and the guards to hold them. Concentrating the best escapers in one place had the opposite effect. They forged uniforms from dyed blankets, tunneled through medieval stone, and in the winter of 1944 to 1945 built a two man glider in the attic above the sentries.

• The first British prisoners were the Laufen Six, officers moved to Colditz in 1940 after trying to tunnel out of another camp.
• The glider, designed by Bill Goldfinch, used stolen floorboards for its frame and bedsheets stiffened with boiled prison porridge for its skin. It was never flown before U.S. troops took the castle in April 1945.
• A replica built from the original drawings flew in 2000, and in 2012 an unmanned replica launched from the castle roof crossed the river and landed in a meadow below.
• Inmates included flying ace Douglas Bader, double Victoria Cross winner Charles Upham, and Desmond Llewelyn, later Q in 17 James Bond films.
• Repairmen kept finding hidden tunnels for decades, along with a secret radio room built by French prisoners. Today the castle is a museum with glass floors over the tunnels, and the old guard quarters are becoming a youth hostel.