Stegeholm's Castle Ruin is located on Slottsholmen by the mouth of Gamlebyviken. The oldest notes about Stegeholms castle are from the 14th century. It was probably built before 1370 by Albert II, Duke of Mecklenburg (the father of King Albert of Sweden). The castle was destroyed by fire in 1517 and rebuilt in 1521. In 1612 it was conquered by Danish. The final destruction appeared in 1677 when Stegeholm was destroyed by Danish-Dutch fleet. Today Västerviks Visfestival (Song festival) is organized in the castle ruins annually.
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.