Fort de Mutzig The Fort de Mutzig , also known as Feste Kaiser Wilhelm II , is located near the town of Mutzig , in the Bas - Rhin departement of France . It is one of the forts built by Germany at the end of the 19th century to defend Strasbourg . It was the first new fortification built in what was then German territory after the invention of high explosives , which rendered earlier masonry fortifications obsolete . Concept . Fort de Mutzig was part of a network of forts surrounding Strasbourg and Metz that had been built by the Germans after the end of the Franco - Prussian War . Earlier forts built from 1872 to 1880 used masonry , which did not resist high explosives or concrete . The Mutzig works were planned as a demonstration of new technology . The western fort , built in 1895 , was built of concrete from the beginning , while the 1893 eastern fort , which had been built in masonry , was reinforced and covered in concrete . Armored observation points and 150mm howitzer turrets were installed , while Mutzig was the first German fort with its own electric generating plant . It also was equipped with a radio link to Strasbourg , infantry shelters and underground living quarters . Costs were estimated at 15 million marks . Description . The fort comprises three main portions . The newest section , and the place used for tours , is located in the northwestern fort . The 1895 west fort is located somewhat to the south , and the eastern fort about one kilometer to the east of the western fort . Together they comprise a " feste " , or fortress , a concept leading eventually to the distributed " ouvrages " of the French Maginot Line fortifications . In 1914 , the fort comprised 50 buildings , with an underground space of approximately 40 , 000 square meters ( 400 , 000 square feet ) . With 22 turrets equipped with 10 cm and 15 cm howitzers at a maximum rate of fire of 6 . 5 tons of shells per minute , Mutzig was one of the strongest forts in Europe . 8000 troops of the German army manned the defenses of Strasbourg at the time . Forces were disposed in the ring of forts around Strasbourg , as well as the Vosges mountains for defense against French forces around Belfort . The fort ' s armament included : Three concrete barracks for the garrison and 18 concrete shelters for infantry were provided , along with four wells , bakeries and other support facilities distributed around the fortification . History . The province of Lorraine had been captured during the Franco - Prussian War , prompting an arms race in the form of fixed fortifications on the parts of France and Germany . The fort saw no significant fighting during the First World War , and was handed over intact to the French Army after the armistice of 1918 , with the exception of about half of its 105mm guns , salvaged in 1917 by the Germans . The French Army designated Mutzig a rear defense of the Rhine frontier . Despite being evacuated in 1940 , it was bombed by the Germans . The eastern fort was the scene of fighting in June 1944 as the Allies advanced to the Rhine . The fort de Mutzig was rated 50 % - 75 % serviceable in 1947 . Museum . A portion of the enormous site , which virtually covers the top of the Breuchstals mountain , was restored and may be visited today . It retains almost all its original equipment .