Trethevy Quoit is a well-preserved megalithic structure between St Cleer and Darite in Cornwall. It is known locally as 'the giant's house'. Like other portal structures of this type, Trethevy Quoit was originally covered by a mound. The remnants of this suggest a diameter of 6.5 metres. The remaining seven stones and the 3.7-metre long and 10.5-ton cover slab were inside the mound. At the upper end of the cover slab is a natural hole, which may have been used for astronomical observation. The group of horizontal stones is composed of a fallen back wall, two overlapping side wall stones, a front stone and a somewhat remote flanking stone. The special feature of Cornish portal graves is that by such stones sometimes a smaller partially closed area is created before the front end. Some stones have hole-like perforations as decoration. The front stone is often called an entrance stone, although in most portal structures this can not be moved. Trevethy Quoit is a rare exception here, because a small rectangular stone moving at the bottom right of the front allows access to the chamber, which is now opened only very rarely.
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.