The Hegau is a formerly volcanic landscape in southern
Germany extending around the industrial city of
Singen (Hohentwiel), between
Lake Constance in the east, the
Rhine River in the south, the
Danube River (Donau) in the north and the Randen - as the southwestern mountains of the
Swabian Alb are called - in the west. The most famous sight of the Hegau is the
Hohentwiel mountain, a volcano that became extinct a long time ago. On top of the mountain lies Hohentwiel fortress. The castle that once stood there was destroyed by French troops during the Napoleonic Wars.
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