Sweden: Kalmar Slott
Kalmar Slott or Castle is one of the best preserved fully-fortified castles in Sweden. This was a strategic location since ancient times and a major fortress was built here in the 12th century, protecting the harbor. In 1397, Kalmar Slott was the place where the historic Kalmar Union treaty of Denmark, Norway, and Sweden was signed. In the early 16th century, kings Gustav, Erik XIV and Johan III rebuilt the medieval castle and made it into a Renaissance palace that stands today.