Kastellet in Copenhagen was constructed in 1663 under King Frederik III, after the original fort on the site was compromised by a Swedish attack in 1658. It was partially rebuilt again in the nineteenth century when the distinctively star-shaped building, flanked by a moat, served as a prison.

During the Second World War, Kastellet was used as a base by German forces whilst they occupied Copenhagen.

Today, still in a great state of preservation, Kastellet is a military base. Its grounds have been turned into a park, which is open to the public, although there is no access to the inside of the fortification.

Kastellet history

King Christian IV of Denmark initiated the construction of a fortress at this vantage point in 1626 with the building of an advanced post to guard the entrance to the port.  King Frederick III succeeded King Christian IV and continued the construction of Kastellet with the commissioning of this star-shaped fortress.

The fortress was a vital part of Copenhagens defences in the years that followed. After the Swedish siege on Copenhagen 1658–1660 the Dutch engineer Henrik Rüse was called in to help rebuild and extend the construction. The fortress played an important in the Battle of Copenhagen when Denmark faced attack from England at the beginning of the 19th century.

The Church at the Citadel was built in 1704 in the Baroque style during the reign of King Frederik IV and a prison complex was built on the rear side of the church in 1725. Holes in the wall between the church and the prison cells made it possible for the prisoners to follow the church services.

The windmill in the southwestern corner of Kastellet was built in 1847, replaces another mill from 1718. Since a fortified city needed secure supplies, including supplies of flour and rolled groats, in the event of siege, numerous windmills were constructed on the bastions. In 1800, a total of 16 windmills were found on the ramparts of Copenhagen. The mill at Kastellet is the last which is still working.

Kastellet was renovated between 1989–1999 with funds from the A.P. Møller and Wife Chastine McKinney Møllers General Fund managed by Maersk.

Kastellet today

The Citadel is still an active military area that belongs to the Danish Defence Ministry.

Despite the continuous military presence in the area, the Citadel is today a peaceful, protected area, serving as a public park as well as a cultural-historical monument. The site includes two small museums with limited opening hours.

There is a changing of the guard ceremony at the Central Guard House every day at midday. Military concerts take place at the drill grounds on summer afternoons at 14.00. The Citadel Church frequently arranges concerts as well.

Getting to Kastellet

The nearest station is Østerport and the fortress can be reached by train, ferry, subway or bus.