Visborg
Region Gotland, Sweden · built 1500
Visborg (also spelled Wisborg) was a medieval fortress located in the town of Visby on the Swedish island of Gotland. Several fortresses were built in Visby over the centuries. The last was the castle built by King Erik of Pomerania, ruler of Kalmar Union. The fortress served as Erik’s residence after his deposition and remained an important Danish stronghold until its destruction in 1679. Today, only fragments of its walls survive overlooking Visby’s harbor.
Monument data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).