St. John's Church was probably built in the first third of the 14th century as a three-nave basilica. The church was damaged in the Russian- Livonian War in the 16th century; lightning has set its spire on fire several times. Some parts of the church were destroyed in the Great Nordic War in 1708.
In the end of 19th century external walls of St. John's Church were cleaned of limewash, the original shape of the choir windows was restored and new external figures were made of instead of the destroyed ones. The building was reconstructed in the Neo-classicism style in 1930’s. During World War II, the church caught fire. The damage was so extensive that an unknown and rich interior decoration was discovered the beneath the destroyed plaster sheet. There have been over a thousand sculptures in the internal and external walls of the construction. There is no other brick church decorated with so much terracotta plastic in Europe.
There are fifteen figures in the triple arch niches of the fronton which represent Judgement Day. On the facade and two sides of the tower there are other figures since the tower's frieze consisting of quaternion foils with a human head continuing in each quaternor foil on the sides of the longitudinal building as well. There are friezes and niches decorated with sculptures in the interior as well.
However, the western wall, with numerous niches with sculptures and pseudotriforium located above the arcades in the niches of which there are figures sitting on a throne, deserves special attention. In the eastern wall, above the triumphal arch, there is a large terracotta group: Christ on a cross and Mary and John beneath the cross.
Reference: Tartu Tourist Information
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.