Swiss National Redoubt Fortification

The National Redoubt encompassed a widely distributed set of fortifications on a general east–west line through the Alps, centering around the major fortress complexes of St. Maurice, St. Gotthard, and Sargans. These fortresses primarily defended the alpine crossings between Germany and Italy and were outside the industrialized and populated regions of Switzerland. These regions were defended by the "Border Line", and the "Army Position" somewhat farther back. While not intended as an impassable barrier, these lines contained significant fortifications, but the National Redoubt was planned as a nearly impregnable complex of fortifications that would deny an aggressor passage over or through the Alps by controlling the major mountain passes and railway tunnels running north-to-south through the region. This strategy was intended to deter an invasion altogether by denying Switzerland's crucial transportation infrastructure to an aggressor. -Wikipedia