Kalmar Castle is one of the greatest Renaissance fortresses in Scandinavia. Its construction began as early as in the twelfth century, when a defensive watchtower was erected. In 1397, the rulers of Denmark, Sweden and Norway formed the Kalmar Union at the castle of Kalmar. However, only two centuries later the representatives of the House of Vasa made Kalmar slott a true royal residence. From the ramparts of the fortress there is a view of Öland, an island located nearby. Tourists can also visit royal chambers, including the chamber of King Eric XIV and the suite of King John III.