Swiss Army fortifications acted as a vital defense against potential WWII invasions, guarding the passage between Walensee and Linthebene-Zürichsee

fortification linthebene swiss history wartime zurichsee defense linth canal heritage alps gruezi museum barrier world war ii glarnerland military walensee protection swiss army bunkers strategic glarus canton landmarks two words passage niederurnen swiss neutrality architecture stronghold region cultural relics heritage site canton strategy alpine world war two swiss history defensive network defensive structure tradition defensive works alpine defense line protective wartime architecture defensive line wartime relics neutral