This fortress was a small infantry blockhouse built during the First World War, once called “Blockhaus Unten” and then renamed “Forte Olimpio” in 1980.
The reinforced concrete fortress consists of a tunnel trench line, covered entirely with a concrete shelter. In the tunnel, there are four machine gun stations and two headlight positions. Since it is located on swampy ground, on the border with the Bolle di Magadino, the building has been built on deep foundations.
The blockhouse was used to defend the Gambarogno cantonal road (left bank of Lake Maggiore) and the Luino – Cadenazzo railway line, both are situated in meters from the complex, and to defend the Magadino artillery factory. Nearby, on the hill side of Magadino, there is a further defence object, which is still easy accessible after having crossed a narrow train line under the passage.
It is an artillery fort originally built between 1912 and 1919. It consists of two canon positions (for 7.5 cm Krupp canons on Sulzer racks), two battle racks for machine guns and two headlight positions. During the Second World War, two new tunnels were digged to separate the accommodations from the work area. During the fifties, a new ammunition emplacement was also installed. This artillery fort could host up to 120 soldiers.
The main fire line of the artillery was the bridge of the cantonal road between Tenero and Gordola (Verzasca Bridge). The secondary target was the right bank of Lago Maggiore (from Ascona to Minusio) thus preventing boats from docking.
Sources and further readings:
“Forte Olimpio” – Fortino Magadino inferiore Unteres Blockhaus Magadino A8064 (Link)