The Piscina Mirabilis was a freshwater cistern on the Bacoli cliff at the western end of the Gulf of Naples. One of the largest freshwater cisterns built by the ancient Romans, it was situated there in order to provide the Roman western imperial fleet at Portus Julius with drinking water.
The cistern was dug entirely out of the tuff cliff face and was 15 metres high, 72 metres long, and 25 metres wide. It was supported by vaulted ceilings and a total of 48 pillars. It was supplied with water from the main Roman aqueduct, the Aqua Augusta, which brought water from sources in Serino near Avellino, 100 kilometres distant, to Naples.
The ancient cistern is currently in private hands, but parts of it may still be visited by the public.
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.