Cairns Castle is a ruined keep, dating from the 15th century. The Crichtons inherited the castle through marriage of the heiress of the castle who was the granddaughter of William de Carnys the original owner.
The castle has an adjoining wing. It has a vaulted basement, a kitchen on the ground floor, and a hall above. All floors were reached by a turnpike stair in the corner between the main block and the wing. There were at least three storeys. The kitchen fireplace was converted into an entrance. The entrance tower to the east no longer exists.
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.