The strongest line of fortifications

As early as 1920, in order to prevent another invasion of the kind experienced in 1914, the French authorities began designing a modern system of defence to run along the borders with Germany, Italy, and then Belgium. Subsequently, from 1929 to 1940, several thousand concrete and steel structures were integrated into the countryside, with the largest ones being interspersed between casemates and artillery observation posts. The goal was for the 700 km line to constitute a defensive barrier, impenetrable due to the crossfire from the different blocks equipped with gun turrets and loopholes. Strategically placed armoured structures were built, half underground, heavily armed and equipped with telephones and electrical generators. Many kilometres of underground passages and railway tracks served access areas and depots. Situated 10 km from the various borders, they were, in reality, part of a carefully organized, 10 to 25 km wide defensive network.

Alsace : 200 km of fortified ramparts

In Alsace, at the heart of the network, the Maginot Line comprises nearly 2,000 fortifications whose wide diversity clearly illustrates the defensive system's design. In 1940, 4 powerful underground fortresses, one such being the Hochwald, the Line's second-largest structure, were occupied by «crews» of up to 1,000 men. Some 200 casemates - holding 15 to 30 men - constituted the other key positions along with look-out posts, some equipped with periscopes, and underground or surface shelters; taken together, these were veritable concrete barracks. Finally, numerous blockhouses lined the 200 km border.

A dense network of structures

The Maginot Line was a defensive line of structures, differing in size, function and placement depending on the topology of the landscape and the importance of the area to be defended. In the region of Alsace, a number of these structures, now restored and open to visitors, attest to the system's organization. The structures presented in this document will provide a complete picture of what constituted France's defensive lines. Generally, the fortifications consisted of 3 types of construction:

• casemates, housing machine guns, positioned every 1,000 to 1,200 meters,
• forts, veritable bastions dominating their positions, housing artillery pieces (long or short) beneath casemates or turrets. These were built 10 to 12 km apart,
• concrete shelters, at ground level or in dug-out structures, designed to house local reserve troops.

A line of anti-tank devices followed by an inner line of meshed steel wire were the twin obstacles constituting the fortified region's initial barrier, some 5 to 15 km from the border. Beyond them were the forts, veritable underground towns, undetectable from the surface. The forts were organized around combat blocks out of which, spaced some 30 to 50 meters apart, emerged turrets equipped with artillery. Below ground, 30 to 40 meters down, several kilometers of passages formed networks linking areas comprising munitions stores, hospitals and showers, barracks, kitchens, electrical generating areas, repair workshops, rooms for neutralizing air contaminated with gas, command posts, and through which ran strings of trucks carrying munitions.