Ertholmene

Ertholmene is a small granite archipelago in the Baltic Sea about 18 kilometers northeast of Gudhjem on Bornholm, marking Denmark's easternmost point. It comprises three main islands, Christianso, the largest at 22.3 hectares, Frederikso at 4 hectares and the uninhabited Graesholm at 11 hectares, along with smaller rocks and skerries, for a total area of 39 hectares and a combined population of 90. A fortress built there in 1684 served as a Danish naval outpost until 1855, and the islands remain under the administration of the Ministry of Defence, with historic granite fortifications that have changed little in three centuries. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/