The plan of the cathedral is largely determined by the steep slope upon which it is built. Before the end of the 19th century, access to the cathedral was by a steep narrow street lined with shops selling pilgrimage souvenirs, which led into a large space under the cathedral floor, and from which pilgrims mounted a separate stairway emerging near the altar. The current stairway was built at the end of the 19th century and goes directly up to the nave.