Santander is an elegant city which extends over a wide bay with views of the Cantabrian Sea. Its historic quarter includes a group of majestic buildings which are situated against an incredible natural backdrop of sea and mountains. The Cantabrian Maritime Museum is in Santander Bay. It is an attractive, modern building, and was born as a tribute to this northern Spanish region and its sea. Over 3,000 square metres, it aims to show the relationship between man and the maritime world throughout history. The majority of the 1,200 objects displayed in the Museo de Prehistoria y Arqueología de Cantabria date from the period between the Palaeolithic and the Iron Age. There are also objects from the Roman period, mostly from Julióbriga and Urdiales Hill-Fort, the ancient Flavióbriga. Iglesia Catedral de Nuestra Señora de la Asunciónt has been a cathedral since the 18th century, but in the 8th century it was an abbey and in the 13th a collegiate church. Its plan is with three naves and four sections. The sanctuary has three polygonal chapels. As for the dome, it has ogives on columns of cruciform pillars. The Parque Natural de las Dunas de Liencres is one of the leading enclaves of dunes along the Cantabrian coastline, given its great landscape, geological, botanical and fauna interest. It stands on the left bank of the mouth of the river Pas, in a peninsula area limited by the Mogro estuary and several adjacent beaches. The extraction of iron in the clay at Parque Natural de Peña Cabarga has been traced back to Roman times.