Description: Erika was a late development in radio guidance, and came too late to have much effect on the Germanís war effort. They had started with Knickebein, then progressed to X-Gerat and Y-Gerat, all of which were far superior to anything the Allies had at that time. The only problem with this system was the large number of bunkers needed which allowed the planes of the RAF to spot the installations. Erika was a long distance navigation system. The transmitting station sent out two tones and equipment on the bomber gave the position to the air crew to within an accuracy of 400 meters. Unfortunately by the time the system was operational the Germans had little or no air force remaining. At St Pierre Eglise there are six installations each with a radio bunker and two generator bunkers. At the heart of the centre was a fortified control room which supervised the transmitting of the signals. By the time the system became available the German had very few aircraft in the sky. I am told that there is a large tunnel system under the town of St Pierre, but as yet I have found no trace.