Gävle Castle is the northest one of so-called Vasa castles, built by Gustav Vasa of Sweden or his sons. The construction started in 1583 by the religious King John III of Sweden. The design was made by Willem Boy and the center of castle was a chapel. The castle was completed in 1597, five years after John's death.
In 1727 the chapel and the top floor were destroyed by fire. Gävle castle stayed damaged until 1741, when it was agreed to rebuilt. The current appearance dates from the design made by Carl Hårleman. In 1754 the reconstruction was complete.
References:Visby Cathedral (also known as St. Mary’s Church) is the only survived medieval church in Visby. It was originally built for German merchants and inaugurated in 1225. Around the year 1350 the church was enlarged and converted into a basilica. The two-storey magazine was also added then above the nave as a warehouse for merchants.
Following the Reformation, the church was transformed into a parish church for the town of Visby. All other churches were abandoned. Shortly after the Reformation, in 1572, Gotland was made into its own Diocese, and the church designated its cathedral.
There is not much left of the original interior. The font is made of local red marble in the 13th century. The pulpit was made in Lübeck in 1684. There are 400 graves under the church floor.