After the end of World War 1, Primož hill became Italian territory following an agreement between Italy, Great Britain, France and Russia alongside South Tyrol, Istria, Dalmatia and various islands in the Adriatic sea. On November 12th, 1920, the border was drawn in accordance with the Treaty of Rapallo, crossing the Pivka basin, on the ridge of the Javorniki mountain chain. Primož's military tunnels were dug in 1930 as a part of the long Alpine Wall, a vast series of Italian Defense fortifications. The tunnels consisted of two lines; one directly on the border, and the second one a few kilometers behind it. Locals were kept away from the tunnels, and were only allowed to bring basic materials and food near its premises. The tunnels were constructed only by verified members of the Italian National Fascist Party. The tunnels were secured with steel plates coated with a thick layer of concrete. The tunnels are long in total, but they were never used for military purposes. After the withdrawal of Italian forces, local people took valuables from the area, and in 1944, German forces destroyed the tunnels in fear that allied Partisans would find military use for them.