The Great dolmen of Dwasieden was excavated in 1970 by Ewald Schuldt. The megalithic site of the Funnelbeaker culture was constructed between 3500 and 2800 B.C. Of the 54 kerb stones - including the four guardian stones - 41 have survived. The rectangular, roughly east-west oriented chamber at the wide end of the frame, with its western entrance and porch consists of seven supporting stones, a half stone the height of the uprights and five slabs, on which there are three large (on the chamber) and three small capstones. Only the central capstone of the chamber is missing. One of the four guardian stones at the southwest end, which had already been overturned in the past, has 40 cup marks, one of the kerb stones has three more. The site is a prime example of the porch dolmen, typical of this region. A two-metre-long porch runs past the support-high half stone to the 4.0 metre long, 1.7 metre wide and 1.4 metre high chamber. The hall consists of red sandstone slabs, annealed flint and a clay floor.
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.