St. Nicholas' Church stands besides one of Germany's oldest manmade waterways, the Frischen Grube, and was dedicated as the church for sailors and fishermen. The 37m high nave is almost the height of the Marienkirche in Lübeck. The protruding northern and southern vestibules that resemble the arms of a transept are also a particular feature of the church. The lavishly adorned southern gable takes a special place in art of brick construction due to its wealth of glazed figured bricks. From St. Nikolai's medieval interior decoration survives a late-thirteenthcentury granite baptismal font and a maritime altarpiece made in the early nineteenthcentury, but the church's interior is chiefly characterized by completely preserved baroque furnishings.
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.