Hitler from retreating with the Wehrmacht into the mountains. By 1940 many of the Alpine countries were under the control of the Axis powers. Austria underwent a political coup that made it part of the Third Reich; France had been invaded and Italy was a fascist regime. Switzerland and Liechtenstein were the only countries to avoid an Axis takeover. The Swiss Confederation mobilized its troops—the country follows the doctrine of "armed neutrality" with all males required to have military training—a number that General Eisenhower estimated to be about 850,000. The Swiss commanders wired the infrastructure leading into the country with explosives, and threatened to destroy bridges, railway tunnels, and roads across passes in the event of a Nazi invasion; and if there was an invasion the Swiss army would then have retreated to the heart of the mountain peaks, where conditions were harsher, and a military invasion would involve difficult and protracted battles. German Ski troops were trained for the war, and battles were waged in mountainous areas such as the battle at Riva Ridge in Italy, where the American 10th Mountain Division encountered heavy resistance in February 1945. At the end of the war, a substantial amount of Nazi plunder was found stored in Austria, where Hitler had hoped to retreat as the war drew to a close. The salt mines surrounding the Altaussee area, where American troops found of gold coins stored in a single mine, were used to store looted art, jewels, and currency; vast quantities of looted art were found and returned to the owners. Largest cities The largest city within the Alps is the city of Grenoble in France. Other larger and important cities within the Alps with over 100,000 inhabitants are in Tyrol with Bolzano (Italy), Trento (Italy) and Innsbruck (Austria). Larger cities outside the Alps are Milan, Verona, Turin (Italy), Munich (Germany), Graz, Vienna, Salzburg (Austria), Ljubljana, Maribor, Kranj (Slovenia), Zurich, Geneva (Switzerland), Nice and Lyon (France). Cities with over 100,000 inhabitants in the Alps are: Alpine people and culture The population of the region is 14 million spread across eight countries. On the rim of the mountains, on the plateaus, and on the plains the economy consists of manufacturing and service jobs whereas in the higher altitudes and the mountains farming is still essential to the economy. Farming and forestry continue to be mainstays of Alpine culture, industries that provide for export