Christiansø is Denmark's easternmost point — a tiny fortress island in the Baltic, about an hour by ferry from Bornholm. The island was built as a naval base by Christian V in the 1680s and the fortifications still dominate the landscape: thick stone walls, the round Store Tarn, and a lighthouse converted from the original defence tower.
No cars, no dogs, and a permanent population of around a hundred. The island is connected by a footbridge to its neighbour Frederiksø, and the two together can be walked in half an hour. Artists and craftspeople have settled here over the years, giving the place a quiet bohemian character. In summer there are a couple of places to eat smoked herring and drink a beer by the harbour.
Christiansø is also one of the best birdwatching spots in Denmark — the island is a nature reserve and sits on a major migration route. Thousands of migratory birds stop here in spring and autumn, and the seabird colonies on neighbouring Graesholmen are protected as a strict reserve.