During World War I, after the Italian Caporetto defeat, Mount Grappa became the most important pillar of Italian defence, and Austrians tried many times to conquer the peak to spread on the Venetian plain from November 11, 1917 to October 24, 1918. The Italians made caves in the rock and built fixed emplacements for the artillery so that they could keep control from the Valderoa Mount to Caprile hill. The most important military work is the Vittorio Emanuele Gallery, which is equipped with water tanks, infirmaries and beds.