The Giants' grave of Su Mont'e s'Abe is an archaeological site located in the municipality of Olbia. Like other giants' tombs of Gallura, it was built in two main phases of construction. In the first stage, during the period of the Bonnanaro culture, it was built an allée couverte tomb; later, in the second phase, during the age Nuragic age (1600 BC approximately), the allée couverte was transformed into a giants' tomb with the realization of the exedra and the erection of the central stele of which few traces remain today.
The tomb, which measures about 28 meters in length and six in width, was excavated and restored in the 1960s.
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.