Christiansø, the oldest naval fortress in the Nordic countries, offers a unique escape. Dating back to 1684, this island group (including Frederiksø, Græsholmen, and other islets) remains remarkably unchanged. Everything here, from structures to flora and fauna, is unconditionally preserved.

Explore the Great Tower, over 330 years old, which now hosts exhibitions, concerts, and cultural events. Learn about life on the fortress and see a model of its 1850s layout at the Little Tower Museum on Frederiksø.

Enjoy dinner at Christiansø Guesthouse, where the famous song "Ud på flisen, Karoline" was inspired. Explore the high-security prison "The Balloon" or stay overnight in one of the cells. Admire the King's Bulwark, larger bulwarks used to defend the fortress. Christiansø is car-free, with hedgehogs as the only land mammals. Explore the island on foot and discover nesting eider ducks. Visit the nearby Græsholmen bird sanctuary, a breeding ground for herring gulls, razorbills, and guillemots. Take a refreshing dip in the Baltic Sea or explore the nooks and crannies of these captivating islands.