The Real Teatro di San Carlo (Royal Theatre of Saint Charles) is located adjacent to the central Piazza del Plebiscito, and connected to the Royal Palace. It is the oldest continuously active venue for public opera in the world, opening in 1737, decades before both the Milan's La Scala and Venice's La Fenice theatres. The construction was ordered by Bourbon King Charles III of Naples. Given its size, structure and antiquity, it was the model for theatres that were later built in Europe.
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.