Ouvrage Pas du Roc, Alpine fortification in Modane, France

Ouvrage Pas du Roc is a Maginot Line artillery work built on and under a small ridge above the Pas du Roc pass, at 2,323 m between the Petit Argentier and the Arrondaz ridge. Its entry is at 2,342 m and the observation block at 2,385 m. Five surface blocks are dispersed to limit bombardment damage, with 2.5 m thick roofs and 2.75 m exposed walls, linked underground by a 60 cm rail gallery. The photograph shows the deep entrance trench, two recessed openings and a reddish-brown observation cupola.

Built as part of the Maginot Line's Alpine extension, the ouvrage was still unfinished when Italy invaded France in June 1940. On 21 June Italian troops cut the cable of its aerial tram; on 24 June the fort, supported by the petit ouvrage d'Arrondaz, repelled the attack of the Superga Division. Italian forces occupied and disarmed it after the 1940 armistice, German troops took over the Alpine positions in 1943, and it was recaptured on 13 September 1944.

The fortification represents French military engineering from the interwar period, showing construction methods and defensive ideas of that time. It stands as evidence of the technical solutions engineers developed during those years.

The ouvrage sits on a small rise above the Pas du Roc, a 2,323 m pass between the Petit Argentier and the Arrondaz ridge, with the entry at 2,342 m and the observation post at 2,385 m. It is reached from the road descending from the Col du Fréjus, about 6 km south of Modane and 1.6 km east of Ouvrage Le Lavoir. The site belongs to private owners who bought it in the early 2000s, so access to the underground galleries depends on their agreement.

A second entrance was planned to link the ouvrage to Pont Nua by aerial tram, but it was never finished. The fort's five surface blocks were spaced apart so that a single shell hit could not knock out more than one, and each combat block kept its own magazines, rest room and ventilation.