The Siegfried Line Museum (Westwallmuseum Irrel) lies near the German-Luxembourg border in the Eifel mountains. It is housed in a bunker that was part of the former Siegfried Line (Westwall), the Katzenkopf Strongpoint (Panzerwerk Katzenkopf), which was built from 1937 to 1939. Together with other bunkers the Panzerwerk Katzenkopf was built to guard the main road from Cologne to the city of Luxembourg. It is the northernmost strongpoint in the Siegfried Line.
These strongpoints differed from the other roughly 15,000 fortifications of the Siegfried Line in having an armoured cupola and wall thicknesses of at least 1.0 metre. 32 examples of such structures were built to construction thickness 'B' with exterior walls of reinforced concrete up to 2 metres thick. Another of these so called B-Werke ('B Works') that has been open to the public since 2006 is B-Werk Besseringen in the Saarland.
The above-ground section of the bunder was blown up in 1947 and its remains were bulldozed into a heap. In July 1976 the excavation of the bunker began the majority of the work being carried out by the Volunteer Fire Service of Irrel. The Siegfried Line Museum has been established on 3 accessible levels of the strongpoint since 1979. There are pictures and weapons of the Second World War period. The museum is only open to casual visitors on Sundays and public holidays (during the summer).
References:Visby Cathedral (also known as St. Mary’s Church) is the only survived medieval church in Visby. It was originally built for German merchants and inaugurated in 1225. Around the year 1350 the church was enlarged and converted into a basilica. The two-storey magazine was also added then above the nave as a warehouse for merchants.
Following the Reformation, the church was transformed into a parish church for the town of Visby. All other churches were abandoned. Shortly after the Reformation, in 1572, Gotland was made into its own Diocese, and the church designated its cathedral.
There is not much left of the original interior. The font is made of local red marble in the 13th century. The pulpit was made in Lübeck in 1684. There are 400 graves under the church floor.