Escape from Colditz Castle: The French Tunnel
Work on the tunnel began in June 1941, and continued for a further eight months.
They began to dig towards the chapel, hoping that they would find a crypt. However, after 4m in this direction with no signs of a crypt, they began to dig upwards towards the floor of the chapel.

From here the tunnel continued underneath the wooden floor of the chapel for a distance of 13.5m. For this to be achieved, seven heavy oak timbers in the floor, measuring 40cm square, had to be cut through. Home-made saws, assembled out of German table knives, were employed for this task. With this completed, the tunnel dropped vertically from the far corner of the chapel a further 5.2m.

From here, the tunnel proceeded out towards the proposed exit, with two further descents, separated by horizontal shafts in the tough stone foundations of the castle. The tunnel now ran a horizontal distance of 44m, reaching a final depth of 8.6m below the ground.
[i]The tunnel itself was a major engineering achievement. It was fully installed with electric lighting along its whole length. The prisoners had wired their circuits to the chapel’s electricity supply. Not only did this allow the tunnellers to see what they were doing, it could also be used as a system with which to signal to them the arrival of any sentries nearby. The entrance to the tunnel was concealed by a hinged stone door which left little trace of any hole. Debris was transported from the working face by means of several sacks moving on sleds, and then hoisted up the clock tower and disposed of in the castle’s attics.
So, tunnelling continued well into 1942. By this time, the Germans knew that the French were digging somewhere in the castle. The security forces were tormented by the sheer arrogance of the French who, working in the dead of night, were aware that the reverberating noise of their tunnelling could be heard by the Germans, but their confidence in its undetectable entrance was total.
However, on 15th January the Germans eventually searched the clock tower which they had sealed off over one year ago. Noises were heard from down below, and after lowering a small boy down the shaft, three French prisoners were found. After searching the cellar thoroughly, the entrance to the tunnel was eventually discovered.
Upon its discovery, the tunnel was only 30 feet short of completion. The earth at this point was soft and easy to work. The Germans had discovered the tunnel just in time.
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The Drainage System Escape Attempt
The sewers under the castle were accessible from various locations. An early British tunnel, the entrance to which was from a manhole cover in the canteen, had made use of these sewers. In June 1944, this tunnel had long been discovered by the Germans. However, the British continued to evaluate the potential usefulness which this network of sewers presented. On 16th June, the guard standing at the archway between the Kommandantur and the approach to the guardhouse heard a noise beneath him. At this spot there was a manhole cover.

He alerted the security officer, who gave the order to lift all three of the manhole covers on the small, cobbled path. Three prisoners, Dick Lorraine, Bos’n Crisp, and Dominic Bruce were consequently pulled out of the sewers underneath. An attempt was made by other prisoners to salvage as much of the tunnel as possible. Three men entered the drains underneath the canteen using a vertical shaft from the old Polish quarters. Unfortunately the German guards beat them to it, and caught them at the bottom of this shaft.
all info about Colditz Castle @ http://www.geocities.com/Pentagon/Bunker/8963/index.html