Middelgrundsfortet is a sea fort located in the Øresund between Copenhagen and Malmö. It was constructed 1890–1894 as a part of Copenhagen's sea-fortifications, partly from material excavated from Frihavnen. It is one of three artificial islands that were created to defend the entrance to Copenhagen's harbor (the other two are Flakfortet and Trekroner Fort).
Middelgrundsfortet was the largest sea fortress in the world, and is still the largest man-made island without abutment, with an area, including wave breakers, of approximately 70 000 m²; the buildings total approximately 15 000 m². A HAWK battery was placed on the island. Until 1984 the fortress was a military area; in 2002 it was sold to a private investor. Ferries connect Middelgrundsfortet with Langelinie, Copenhagen.
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.