The first permanent inhabitation in Ertholmene, generally called Christiansø, 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 Christiansø and Frederiksø in 1684 which served as an outpost for the Danish Navy until 1855. The islands' external appearance has changed very little in over 300 years. Girdled by thick granite walls with old cannons pointed seaward, Christiansø is a picturesque tourist spot seemingly frozen in time. A former part of the fort, Store Tårn has housed the Christiansø Lighthouse for the past 200 years, and a small round tower on Frederiksø, Lille Tårn, serves as a museum.
References:Manarola is a small town, a frazione of the comune of Riomaggiore. It is the second-smallest of the famous Cinque Terre towns frequented by tourists, with a population of 353.
Manarola may be the oldest of the towns in the Cinque Terre, with the cornerstone of the church, San Lorenzo, dating from 1338. The local dialect is Manarolese, which is marginally different from the dialects in the nearby area. The name 'Manarola' is probably a dialectical evolution of the Latin, 'magna rota'. In the Manarolese dialect this was changed to 'magna roea' which means 'large wheel', in reference to the mill wheel in the town.
Manarola's primary industries have traditionally been fishing and wine-making. The local wine, called Sciacchetrà, is especially renowned; references from Roman writings mention the high quality of the wine produced in the region.