The Fula Gap is a region of lower elevation between the former East German border and Frankfurt, (West) Germany. Named for the town of Fulda, the Fulda Gap was strategically important during the Cold War. "Gap" refers to a corridor of lowlands (between the Hohe Rhön and Knüllgebirge mountains, and between the Spessart and the Vogelsberg mountains), which is suitable for operations by large-scale armored forces. The Fulda Gap was one of two obvious routes for a hypothetical Soviet tank attack upon West Germany from Eastern Europe, especially East Germany; the second route was the North German Plain, and the third, less likely, route was up through the Danube River valley in Austria.