To the northeast of Bornholm lies a group of islands called Ertholmene (Pea Islands), which can be reached by boat from Allinge, Gudhjem, and Svaneke.
On the main island of Christiansø are extensive fortifications installed by Christian V in 1684. When the port lost its importance as a naval base in the 19th century, it became something of a magnet for poets and artists.
