Main entrance The fortified entrance block with the trench which descends to the door. On the right you see the cement prolongation of the photophonic channel whose opening is obstructed by earth (24/06/1999).

Only the upper part of the front wall of the fortified entrance block is visible above ground. The metal door, which has been completely removed, was located in a cement trench which was reached by descending some steps.

Due to the presence of "every possible kind" of refuse in the first part of the corridor, it is not particularly pleasant to enter the works.

The fortified entrance block includes an emergency exit, which leaves from the left wall of the corridor, and a photophonic station for communication with Center 22 (Roncia Defensive Line), located near the curve in the corridor.

After this a stairway descends to the location of the power supply group and the inside of the works.