Walking along the trail surrounding the Sacred Area of Mt. San Michele, between Heights 2 and 3, you can see the entrance gate of the Schönburgtunnel, one of the main defensive structures built by the Austro-Hungarian Army. Its construction was started by the Seventh Feldjager Battalion in 1915, and the tunnel was dedicated to the General of the Sixth Infantry Division, Alois von Schönburg Hartenstein, one of the key players of the Third Battle of the Isonzo in October 1915.
The tunnel cuts across the whole mount and reaches the opposite side. It was used as a shelter and also as a passageway for the Austro-Hungarian reserves heading to the front line. On the other side, a machine-gun pit presided over the territory between Heights 2 and 3.
Due to its collapse, now this tunnel can only be partly visited, thanks to the efforts by the Karst Speleological Association of San Martino del Carso. The entrance still retains its original structure and stones, as you can clearly see on the pediment bearing the original wording FJB 7 Schönburgtunnel FEB 1916, indicating the Battalion who dug it and the date of completion.
