Copenhagen: Kastellet.

“Kastellet, located in Copenhagen, is one of the best preserved star fortresses in Northern Europe. It is constructed in the form of a pentagram with bastions at its corners. Kastellet was continuous with the ring of bastioned ramparts which used to encircle Copenhagen but of which only the ramparts of Christianshavn remain today.

“King Christian IV of Denmark initiated Kastellet’s construction in 1626 with the building of an advanced post, the Sankt Annæ Skanse (English: St. Anne’s Redoubt), on the coast north of the city. The redoubt guarded the entrance to the port, together with a blockhouse that was constructed north of Christianshavn, which had just been founded on the other side of the strait between Zealand and Amager. At that time the fortifications only reached as far north as present day Nørreport station, and then returned south east to meet the coast at Bremerholm, the Royal Shipyard. However, part of the king’s plan was to expand the area of the fortified city by abandoning the old East Rampart and instead extend the rampart straight north to connect it to Sankt Annæ Skanse. This plan was not completed until the mid-1640s, shortly after King Frederick III succeeded King Christian IV.”