The Roman theatre of Cádiz is an ancient structure discovered in 1980. The theatre, which was likely built during the 1st century BC and was one of the largest ever built in the Roman empire, was abandoned in the 4th century and, in the 13th century, a fortress was built on its ruins by order of King Alfonso X of Castile.
The theatre featured a cavea with a diameter of more than 120 meters, and could house some 10,000 spectators. The theatre was one of the few Roman structures of ancient Hispania mentioned by classical authors, including Cicero and Strabo. Excavations in the site have also found remains of a quarter dating to the taifa period, Almohad houses and 17th century pits.
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.