Known for its eye-catching Romanesque and Gothic architecture, the Nidaros Cathedral is one of the most important religious monuments in northern Europe. The end point of pilgrims’ trails from all across Scandinavia, the cathedral is built over the burial site of Saint Olav, the king of Norway in the 11th century, who became the patron saint of the nation. Don’t miss the adjacent Archbishop’s Palace, where you can get a glimpse of the impressive crown jewels used during the coronation ceremonies. The crypt is also worth a look for its macabre collection of marble gravestones.