  thumb|view from christiansÃ¸ to frederiksÃ¸ ertholmene, generally called christiansÃ¸, is a small archipelago situated approximately 18&nbsp;km northeast of bornholm in the baltic sea. its permanent population is 92 () and its area is . ertholmene belongs to denmark and has the country's easternmost point. ertholmene consists of three main islands, christiansÃ¸ (named after king christian v), frederiksÃ¸ (named after king frederick iv) and grÃ¦sholm, plus a number of minor rocks and skerries. the best known of the latter are tat and ÃsterskÃ¦r, denmark's easternmost point. christiansÃ¸ makes up 22.3 hectares, frederiksÃ¸ 4, and grÃ¦sholm 11 hectares. only christiansÃ¸ and frederiksÃ¸ are inhabited, while grÃ¦sholm is a bird reserve. the sound between christiansÃ¸ and frederiksÃ¸, a well-sheltered natural harbour, is crossed by a pedestrian bridge that is pulled aside to accommodate larger vessels. ==history== fishermen from bornholm have used ertholmene for temporary shelter since the middle ages. the first permanent inhabitation was the result of the danish-swedish conflicts in the late 17th century. as denmark needed a naval base in the central baltic sea, a fort was built on christiansÃ¸ and frederiksÃ¸ in 1684 which served as an outpost for the danish navy until 1855. christiansÃ¸ church originally served the garrison.otto norn, c. g. schultz, erik skov, "christiansÃ¸ kirke": bornholms nÃ¸rre herred, danmarks kirker, bornholm, nationalmuseet, gad, 1954, pp. 576â583.  retrieved 2 october 2012 the population peaked at the census in 1810 which showed 829 inhabitants. they were there because of the gunboat war. many of the historical buildings now serve as living quarters for the local population, and some are rented, year after year, to regular summer residents. the islands' external appearance has changed very little in over 300 years. girdled by thick granite walls with old cannons pointed seaward, christiansÃ¸ is a picturesque tourist spot seemingly frozen in time. a former part of the fort, store tÃ¥rn has housed the [[christiansÃ¸ 
Danish_islands_in_the_Baltic Forts_in_Denmark Islands_of_Denmark Ramsar_sites_in_Denmark