During the Cold War, the Fulda Gap offered one of the two obvious routes for a hypothetical Soviet tank attack on West Germany from Eastern Europe (especially from East Germany); the other route crossed the North German Plain. A third, less likely, route involved travelling up through the Danube River valley through neutral Austria. The concept of a major tank battle along the Fulda Gap became a predominant element of North Atlantic Treaty Organization (NATO) war planning during the Cold War. With such an eventuality in mind, weapons were evolved such as nuclear tube and missile artillery, the nuclear recoilless gun/tactical launcher Davy Crockett, Special Atomic Demolition Munitions, the AH-64 Apache attack helicopter, and A-10 ground attack aircraft.