In The Great Escape, the tunnel used for the prisoners’ planned escape is called Tunnel Harry.
The 1963 film dramatizes a mass escape attempt by Allied prisoners from Stalag Luft III, a German prisoner-of-war camp. The prisoners dig three tunnels and give them the names Tom, Dick, and Harry so that work can continue even if one tunnel is discovered.
Tunnel Harry is the one used in the escape attempt shown in the film. In the historical escape, 76 prisoners got out before the tunnel was discovered. The movie changes or compresses several events and characters, but it preserves the basic three-tunnel plan and the significance of Harry.
The title can cause another confusion: “The Great Escape” is also the name commonly given to the real 1944 escape. The camp held captured airmen, rather than prisoners from every branch of the Allied forces.