About Christiansø

The Ertholmene islands lie enticingly on the horizon northeast of Bornholm. The archipelago consists of two inhabited islands, Christiansø and Frederiksø, as well as the bird sanctuary Græsholmen and a number of larger and smaller skerries.
From being a collection of desolate rock formations rising from the sea, the islands have today transformed into a popular excursion destination for tourists.

It all began in 1684 when Christian V (1670 - 1699) decided that a defensive fortification should be built for the fleet's ships in the Baltic Sea. With the Peace of Roskilde in 1658, Denmark had lost Skåne, Halland, and Blekinge, making it necessary to control the movements of the Swedish fleet in the Baltic Sea. On Ertholmene, there was a natural harbor between two of the islands. Here, the fortress Christiansø, the world's first naval base, was built. First, the two characteristic towers, St. Tårn on Christiansø and Lilletårn on Frederiksø, were erected.

On both islands, bastions and a ring wall were built facing the open sea. Well-sheltered behind them lie the fortress's many other buildings. An impressive structure that was worked on throughout the entire period of the fortress. In the harbor, the ships of the Danish fleet could seek protection, fetch water and provisions, and have damages repaired during their voyages in the Baltic Sea.

Within these historic settings, a well-functioning small civilian community with approximately 95 residents exists today. On Christiansø, for example, there is a school, church, lighthouse, post office, library, community hall, museum, campsite, grocery store, and inn. The island has its own fire and rescue service, electricity, and waterworks.