Karlskrona was founded in 1680 when King Karl XI needed a southern naval base that wouldn't freeze in winter. He chose a cluster of islands at the southeastern tip of Sweden, laid out a baroque city on a grid, and built Sweden's great war fleet here. The whole thing — dockyard, churches, fortifications, artisan quarters — was designated a UNESCO World Heritage Site in 1998, and it remains one of the best-preserved naval cities in the world.
The city sits on the island of Trossö, connected to the mainland by bridges, with the Baltic spreading out in all directions. The grid plan still holds: broad streets meeting at right angles, two baroque churches flanking the great central Stortorget, and the naval dockyard at one end. The weather is generally mild and sunny compared to the rest of Sweden — the Baltic coast of Blekinge sees more sun than almost anywhere north of Malmö — though October to December can be persistently grey.
The Admiralty Church, the largest wooden church in Sweden, stands a short walk from the square, and the artisan quarter of Björkholmen preserves the 18th-century streets where the fleet's craftsmen lived. At the dockyard, the Polhem dry dock — completed in 1724 and still the oldest functioning dry dock in the world — gives a visceral sense of what it took to keep a great navy running.
The islands of the archipelago, until recently off-limits to foreigners as a military zone, are now open and worth exploring. Free ferries run frequently, and you can cycle or walk through a landscape of granite, heather, and ice-blue inlets that feels quite different from the formal streets of the city centre.