A short ferry ride from Helsinki’s Southern Harbor next to Market Square is the UNESCO World Heritage site of Suomenlinna Fortress. One of Finland’s most visited tourist sites, the fortress spans a series of eight small rocky skerries, or islands, where it once served as a vast maritime fortress.

Today, Suomenlinna is home to about 800 permanent residents. Most of the site is under civilian administration, with the exception of an islet that’s occupied by Finland’s Naval Academy. Full-scale restoration of the historic buildings began in 1973 following the army’s official departure, with authentic traditional building practices used to restore the embankments, earthworks and collection of buildings. Efforts included converting barracks and ramparts into usable living and business spaces; and while artisans, stone masons and engineers oversee the structural details of the ongoing project, researchers have embarked on scientific studies of how salt water and salt-tinged winds cause even massive brickworks to deteriorate. Not all the work is taking place on terra firma: Underwater teams from the Maritime Archaeology Unit of the National Board of Antiquities are documenting artifacts that include 18 submerged structures and dozens of sunken wrecks from a variety of historical periods. Stroll the island, have lunch at one of the local cafés and gaze out at the ever-present sea.