Schwanau island in Lake Lauerz is occupied by a ruined castle, a chapel and a restaurant. Traces of occupation on the island date back to around 1200 BC. There is little documentary evidence relating to the castle, but it is believed to have been built at the end of the 12th century and to have been ruined, probably as a result of a fire, as early as the middle of the 13th century.
The island in known to have been occupied by hermits at various times, including the 17th and 18th centuries. In 1684 a chapel was built on the island, but this was destroyed by the tsunami that followed the 1806 Goldau landslide. In 1808 the council of the church in Schwyz sold the island to General Ludwig Auf der Maur on the provision that he rebuild the chapel. The island remained in the possession of the general's descendants until 1967, when it was purchased by the canton of Schwyz. In 2009 it was completely renovated.
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.