The Cyriaksburg Fortress is situated on a hill outside the city gates of Erfurt. The construction was started in 1480 but not completed until about 1604. The shape of the foundations is like a rectangle with unequal sides. Two strong round towers from 1528 have been preserved. One of them is now used as a viewing tower and the other one houses an observatory. The moat is also partly visible.
From 1631 to 1649, during the Thirty Years' War, Cyriaksburg was occupied by the Swedes. During that time it is said that the famous physicist Otto von Guericke from Magdeburg assisted in fortifying parts of the castle. The remains visible today date back mainly to 1824 until 1830, when the Prussians converted the castle into a fortress. The underground parts house a well of about 40 metres depth for drinking water and for water to extinguish fires. This well dates back to 1530. The brick vaults above the well date back to 1829.
Parts of the fortress were dismantled between 1874 and 1900. The surrounding areas were gradually planted with shrubs and flowers and opened to the public. The rooms of the Cyriaksburg Castle are now used for the permanent exhibition of the German Museum for Horticulture.
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.