Gerulata was a Roman military camp located near today's Rusovce, a borough of Bratislava. It was part of the Roman province Pannonia and built in the 2nd century as a part of the Limes Romanus system. It was abandoned in the 4th century, when Roman legions withdrew from Pannonia.
Today there is a museum, which is part of the Bratislava City Museum. The most preserved object is a quadrilateral building 30 metres long and 30 metres wide, with 2.4 metre thick walls.
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.