The Proserpina Dam is a Roman gravity dam in Mérida, Spain, dating to the 1st or 2nd century AD. It was built as part of the infrastructure which supplied the city of Emerita Augusta with water.
After the fall of the Roman Empire, the Milagros aqueduct leading to the city fell into decay, but the earth dam with retaining wall is still in use.
It is also part of the Archaeological Ensemble of Mérida, an UNESCO World Heritage Site since 1993.
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.