St Magnus Cathedral is the oldest cathedral in Scotland and, at 50 metres tall, an astonishing presence in a town of ten thousand people. Earl Rögnvald Kali Kolsson laid the foundation stone in 1137, vowing to build "a stone minster more magnificent than any in Orkney" in honour of his martyred uncle Magnus. Construction continued for nearly three centuries, with the result being a building that moves between Romanesque rounded arches and later Gothic additions — built from alternating bands of red sandstone from Kirkwall and yellow sandstone from the island of Eday.
Inside, the cathedral is atmospheric rather than ornate: thick Norman pillars, worn flagstones, and memorial tablets to Orcadian explorers and seafarers. A dungeon known as "Marwick's Hole" was used between 1594 and 1708 to hold those accused of witchcraft. The organ, installed in 1925, fills the nave impressively on occasion. This is still an active Church of Scotland parish church — services are held throughout the week — and it is free to enter.