The piers and sheds of Lower Fort Mason were originally built from 1912 to warehouse army supplies and provide docking space for army transport ships. By this time, the US Army began to build new posts in Hawaii, the Philippines, and various other Pacific islands. Most of the materiel for those posts was shipped through San Francisco. By 1915, the three piers together with their associated warehouse had been completed, and Fort Mason Tunnel driven under Upper Fort Mason to connect with the railroad network along the Embarcadero.