CIRCUS 157 is the code name for a Royal Air Force operation on 5 May 1942. Six bombers escorted by Spitfires are to attack a power station in Lille (Northern France). Technical problems and heavy cloud hamper the operation. On their way back German fighter planes attack. During the ensuing dogfight five Spitfires crash alongside the border between France and Flanders. Four of the five pilots get killed .

Two cycling routes bring this forgotten World War 2-story to life. It is a gripping story, with a lot of human tragedy, both in the air and on the ground. Follow the junction points and discover the crashsites, the monuments and the cemeteries of the Circus 157 pilots.