If you think Bornholm is as remote as Denmark gets, you’d be wrong. Even further east, way out in the Baltic, is tiny Christiansø, an intensely atmospheric 17th-century island fortress about 500m long. It's an hour’s sail northeast of Bornholm (departing from Gudhjem), and makes an idyllic day-trip destination.
There is something of the Faroe Islands about Christiansø’s landscape (on a much less epic scale), with its rugged, moss-covered rocks, historic stone buildings and even hardier people. There is a real sense, too, that you are travelling back in time when you visit here, particularly if you stay overnight at the charming Christiansø Gæstgiveri and get to experience the island once most of the day-trippers have gone.