Visby Cathedral.

As the only one of Visby’s thirteen medieval churches to survive the Reformation and subsequent fires intact, Saint Mary’s Cathedral stands as a resilient anchor within the walled city. Originally built in the 13th century to serve German merchants, the structure evolved from a Romanesque basilica into a Gothic hall church, a transformation visible in its mix of heavy masonry and soaring pointed arches. Its silhouette is defined by a massive square western tower and two smaller octagonal towers at the east, while the southern "bridal portal" offers a masterclass in medieval stonework. Inside, the atmosphere is dictated by light filtering through 20th-century stained glass and a collection of historic organs. Unlike the skeletal ruins elsewhere in town, this is a living space where 800 years of Baltic history remain sheltered under a functional roof.