The Fort de Mutzig, also known as Feste Kaiser Wilhelm II, is located near the town of Mutzig. It is one of the fortifications built by Germany at the end of the 19th century to defend Strasbourg.
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 fortress 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 105 mm guns, salvaged in 1917 by the Germans. The French Army designated Mutzig a rear defense of the Rhine frontier.
During the Second World War the fortress was occupied for a time by German artillery and infantry regiments but on June 13, 1940 forces were ordered to evacuate the area and all the guns were decommissioned. Despite this, it was later bombed by the German Luftwaffe when it was suspected that French troops had taken possession. However, part of the Wehrmacht's 215th Infantry Division was in fact in the fortress at the time and more than 70 German soldiers were killed in the Stuka attack.
In November 1944 the US Third Infantry Division took the fortress, which was then thinly occupied by German forces who were forced to surrender after a short time for want of ordnance and reinforcements.
After the Second World War the fortress was used by the French Army for exercises up until the 1960s when it was abandoned but remained in the possession of the military. As the fortress never saw substantial military action, it remains one of the best preserved pre-World War I sites in existence. This enormous site, which retains almost all its original equipment, has been under a process of restoration by a joint German–French group since 1984 and in 1995 a Museum was opened to the public together with some restored areas of the site. Local historical reenactment groups also make use of the fortress. Since 2014 the fortress has been known by its original name, the Kaiser Wilhelm II fortress.
References:Sigmaringen Castle was first mentioned in the year 1077 in the chronicles of Petershausen monastery. The oldest parts of the castle are concealed beneath the alterations made during the 17th and the 19th centuries. The secret of the earliest settlement built on this defendable rock will never be fully revealed: large-scale excavation work would be necessary, which the extensive land development renders impossible. Judging from the many Roman remains unearthed in the area around Sigmaringen, the 12th century keep known as the 'Roman Tower' could be traced back to a Roman predecessor.
The castle remains that have been preserved (gate, great hall and keep) date back to the Staufer period around 1200. The castle remains were integrated into subsequent buildings. The foundations of the castle buildings are to a large extent identical to the surrounding castle wall.
These remains give us a good idea of how the castle might have looked during the 12th century.