John Weir, an RCAF Spitfire pilot in WWII taken POW, talks about the planning of the tunnels in Stalag Luft III. John, with Wally Floody, devised the tunnel support system for "Tom, Dick and Harry". John talks about "Big X" and the tunneling process, and the challenges that they faced. He also explains why the tunnel was short for the night of the escape.  John was born in Toronto and joined the RCAF in September 1939. He flew spitfires over England, France and the English Channel with the renowned 401 Squadron, but was shot down in November 1941. Despite several escape attempts, he spent the rest of the war as a PoW, and the last two years in Stalag Luft III. John was one of the key figures in the "Great Escape," but missed the actual escape due to being shipping out of camp just prior to that fateful night. He survived the deadly winter march to Lubeck in 1945, and returned to Canada where he still lives.