sentences:  Formerly, the visitor passed through a porch standing well out from the building and, after descending beneath the pavement, emerged by a stairway in front of the high altar.The principal stairway is now covered by a bold vaulting that serves as base for one half of the church.The façade, striped in courses of white sandstone and black volcanic breccia, is reached by a flight of sixty steps, and consists of three orders