Zarafona Castle is a good sample of late medieval fortification architecture. It is in relatively good condition According to an inscription found on the west external wall, the castle was constructed in the period that the Despotate of Moreas was governed by Theodoros II Paleologos (1407-1448). Therefore it was a construction of the first half of the 15th century, part of the effort of the Byzantines to confront the Ottoman threat.
The castle has an almost trapezoid layout and covers an area of 745 square meters. There are 3 towers, two at the west wind and two at the east. The walls are divided in 5 straight parts of vertical walls.
The central tower is much higher than the other buildings and the walls. It has 3 levels. The ground-floor houses a cistern.
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.