This blockhouse is part of the defenses of the railroad tunnel under the St. Gotthard Pass. The lower blockhouse has dissapeared with the construction of a new road near the tunnel. It is made of granit plates. The Swiss used this material until 1914. It is interesting to nte that a flame thrower was also a part of the defenses of the tunnel. The flames would consume all the oxygen in the tunnel and kill the enemy soldiers. So it would create the same inferno as during the accidents which occured some time ago in tunnels.