The exact construction period of Rõngu vassal fortress is not known, but it was probably completed around 1340. The Holy Cross Chapel, located here, was mentioned in the year 1413. During the Middle Ages, the stronghold belonged to the Tödwen family. The fortress was destroyed by the troops of the Order in 1558 and burnt by Jesuits in 1625.
The majority of the castle's layout is not visible over the ground surface. An approximately 25-metre-long section from the outer wall of the eastern side has been preserved, there is also the opening of the main gate. The ruins have not been conserved and fall down gradually. The castle hill is surrounded by a 12-hectare park, which has beautiful majestic oaks, larches and other ancient trees.
Reference: Võrtsjärv Travel Guide
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.