European Culture Route Fortified Monuments - FORTE CULTURA®

Maginot Line Lembach - Four à Chaux France

The bunker landscape of the Maginot Line in Alsace

Experience European history up close

Take to the airy heights and visit this historic structure that towers over the village of Lembach. Experience an impressive look back into the past.
Built between 1930 and 1935, Four à Chaux is one of the most important sites of the Maginot Line in Alsace and was intended to secure the valley of the Sûre. This mountain fortress, located south of Lembach, extends over some 5 km of underground galleries up to 30 m below ground and covers an area of 26 ha. The Four à Chaux fortress was built with 6 fighting blocks, 3 of which were for artillery, and has as a special feature an inclined plane unique in Alsace. The name Four à Chaux refers to a former lime kiln that was in operation nearby until 1939 and which gave its name to the entire area around it. This name later became the common, civilian name; in wartime, the code name was A4. The number of troops in the fortress was about 580 men.
The visitor will discover some of the equipment still in place and will receive information on how it worked as well as the importance of the Maginot Line during the Second World War.
The Four à Chaux site is one of the 108 forts of the Maginot Line that stretch 750 km along the north-western border of France. The site belongs to the Secteur Fortifié des Vosges area.
The fort was occupied in 1938 by troops of the "165e Régiment d'Infanterie de Forteresse (165e RIF)" (165th Fortified Infantry Regiment), the "168e Régiment d'Artillerie de Position (168e RAP)" (168th Position Artillery Regiment) and the "15e Régiment du Génie" (15th Engineer Regiment). From here, fire was first opened on German patrols on 20 May 1940.
The French troops remained in the fortress after the armistice of 22 June 1940 until 1 July 1940, when they were forced by the French supreme command to surrender to the German troops. This affected the entire Maginot Line.
Between 1951 and 1953, the French army had the artillery works restored except for Block 1. It still belongs to the air force today. The Lembach & Surroundings Tourist Association has been able to open the artillery works to the public since 1983. In addition to the actual facility (crew entrance, barracks, Block 2, etc.), a museum with a memorial to the French and German fallen can be visited. Individual tours will not be conducted.
The guided tour offered (1.5 km) starts at the crew entrance, leads through the barracks, kitchen, telecommunications centre, command post to bunker 2 with a 75-mm gun turret model 1932. Then it goes down the inclined plane with the inclined lift to the area of the ammunition entrance. In addition to the engine room and the power centre, there is also a small museum here. At the end of the tour, you leave the factory again through the munitions entrance.
The above-ground area of the factory is not open to the public. It is a military area and may not be entered. It is life-threatening to walk on it because of the infantry obstacles still present there (including sunken steel spikes).

Experience World

Bunkers/ Battle Blocks


The Four à Chaux was equipped with 6 fighting blocks; blocks 1-3 for the artillery, blocks 4 and 5 for the infantry and block 6 for the infantry casemate. The original planning envisaged 8 combat blocks. However, only 6 were realised during construction.
The combat blocks are connected to each other via a tunnel system. Above ground, the fighting blocks with different equipment and armament for the corresponding weapon systems are visible as domes. The fighting blocks are each equipped with one or two domes (bells).
Turrets for cannons and mortars, for rapid-fire rifles, grenade launchers and tank barrages could be extended from inside the bunker and still convey concepts such as "invincibility" and "fortitude" today. In the outer area around the bunkers, semi-concealed, heavily reinforced retractable domes for guns and well-camouflaged emergency and escape exits in the woods still bear witness to the formidable defence installations.
Block 1 was massively destroyed by blasting by the German Wehrmacht after 1940 and was not repaired.

Diagonal lift


Since the ammunition entrance of the Four à Chaux is much lower than the crew entrance, an inclined plane leads up to the connecting corridors of the other bunkers. An inclined hoist with counterweight and winch ran upwards on this level. Such an inclined lift leading from the bottom to the top is unique in northern France, as all other inclined lifts lead downwards.

Underground barracks


As usual for such installations, the underground barracks consisted of a supply department for stocking food, a canteen kitchen, rest and stand-by rooms with showers and toilets, a medical department with an operating theatre, and a technical department with power and heating plants and workshops. Fresh water was drawn from an artesian well 214 m deep.

Infirmary Kitchen Beds in the troop dormitory

Tour Offers and Information

Guided tours in the Four à Chaux - Maginot line

From 1 May to 30 September, guided tours of the Four à Chaux plant will be offered in French, German or English.
The guided tours last approx. 2 hours. The 1.5 km walk takes you through two floors. The constant temperature of 13° makes warm clothing necessary even in summer.

Adults: 8,00 €
Student: 6,00 €
Child (6 to 17 years): 5,00 €
Family with 1 child (6 to 17 years): 18,00 €
Family with 2 children (6 to 17 years): 22,00 € (+ 4,00 € per additional child + 7,00 € per additional adult)

(Fleckenstein Castle / Maginot Line - Four à Chaux)
Adult : 10,50 €
Child (6 to 17 ) : 6,50 €

Groups from 20 persons (with reservation)
Adult group : 7,00 € / person
School group (6 to 17 years) : 4,00 € / pupil
Group of less than 20 people : 160,00 € (flat fee)
Guided tours for groups are possible all year round with reservation.


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Monument and History


The Maginot Line was often seen as a rampart to defend the Franco-German border. However, the line actually extended from the north of France to the Mediterranean. The area used to defend the Franco-Italian border was also called the Alpine Line.

Historical overview - Work Four à Chaux

1930-1935 Construction of the factory
1938 First occupation of the Work Four à Chaux
Mai 1940 Artillery operations against enemy patrol
24.06.1940 last artillery salvos fired
01.07.1940 Occupation of the Four à Chaux surrenders 6 days after the armistice with full martial honours and is disarmed on 02.07.1940
1940-1944 Occupation of the work by the German Wehrmacht
1951-1953 Major reconstruction Work in the Work Four à Chaux
1983 Opening to the public by the Tourist Association of Lembach and Environs (S.I.L.E.)

Quelle: © Four à Chaux
Quelle: © Four à Chaux
Quelle: © Four à Chaux
Quelle: © Four à Chaux


The fortification was built into an approximately 270 m high mountain between the Sauer and the Schmelzbach. Due to the very narrow ridge, only a very compact artillery piece with an extension of about 650, which was small for the Maginot Line, was possible. A total of eight blocks were built between 1930 and 1935. Access to the plant was at ground level via the crew entrance. The lower ammunition entrance was equipped with an electric inclined lift that transported ammunition and supplies upwards. Such an inclined lift leading upwards is unique in northern France because all other inclined lifts lead downwards. At first, the goods were delivered by lorry, but later, from May 1940, they were transported by the field railway, which had then been completed.
Another unusual feature of the Four à Chaux is the fountain. Next to the power station is an artesian well with a depth of 214 metres. This well produced 6000 litres of drinking water per hour at a temperature of 16 degrees. It supplied three water tanks with a total capacity of 150 000 litres.
Plan of the Work Four à Chaux

Quelle: © Four à Chaux
Quelle: © Four à Chaux - Maginot Linie
Quelle: © Four à Chaux - Maginot Linie
Quelle: © Four à Chaux - Maginot Linie

Nature Experience

The Work Four á Chaux is located in the middle of the Vosges du Nord regional nature park. TheTree top walk - Chemin des Cimes Alsace offers visitors the opportunity to walk among the trees and relax. With a trail ranging in height from 5 to 23 metres and a total length of 1050 metres, the Chemin des Cimes Alsace offers a unique experience of nature. The highest point is the 29-metre-high panoramic tower with a 75-metre-long slide in the middle. Once you reach the top of the tower, you will be surprised by a unique view. As one of the highest points in the foothills of the Vosges, the tower offers you a 360° panoramic view of the Rhine plain, the Black Forest and the Northern Vosges. The path is designed to be barrier-free. With a maximum gradient of 6%, it is possible for people in wheelchairs and families with prams to enjoy a pleasant walk.
A restaurant with terrace and winter garden offers tasty local specialities.A wide range of sustainable and local products is available in the souvenir shop.
Worth seeing in the Northern Vosges Regional Nature Park are the numerous medieval castles: high-lying ruins are among the cultural sites to be discovered and offer attractive opportunities for climbing enthusiasts. The UNESCO Biosphere Reserve Pfälzerwald-Nordvogesen offers impressive landscapes as well as a wide range of activities and sights. The Visitor mine Iron mine St. Anna Stollen is both a technical cultural monument and a bat roost. The Fleckenstein Castle with the Fleckenstein Castle - Children's Adventure World is a family highlight not far from the Four à Chaux works.

Quelle: Krappenfels Richtung Fleckenstein © J.Isenmann-PNRVN
Quelle: © Chateau Fleckenstein
Quelle: © Chateau Fleckenstein
Quelle: © Chemin des Cimes Alsace Drachenbronn