The cathedral was built in the 12th - 13th centuries. It has three entrances: the north door or Portada de Santa María; the south door, El Portal or Portada de los Peones, and the main door or Portada del Juicio Final, a proto-Gothic portico depicting the Last Judgement. The cathedral has a Latin cross plan with three naves, with an outstanding transept in a fully Gothic style. The ceiling consists of groin vaults, except for the side chapels, which have round and pointed barrel vaults. Inside there is a notable altarpiece painted by Pedro Díaz de Oviedo. There is also an interesting 12th century stone sculpture of the Virgin, known as the Virgen Blanca. A Romanesque tower stands to one side of the portico of the Last Judgement, and a brick Renaissance tower on the other side.