This tour guide describes a 8 km cycling route called the "Three Bridges Tour" around Mainz, Germany. The route crosses three bridges - the Theodor-Heuss Bridge, the South Railway Bridge, and the Main Bridge of Kostheim. Points of interest along the route include the Gustavsburg checkpoint, the Maaraue recreational park, the Reduit of Mainz-Kastel former fortress, and the town of Kastel. The tour is suitable for families and has good public transportation connections.