Powerful in its sobriety, this grey Gothic edifice looms heavily over the central square. The earliest parts of the cathedral date from 1390 but it's dotted with Manueline and Renaissance ornamentation. The most striking feature in the immense, granite interior is the four-storey Renaissance altarpiece attributed to Jean de Rouen (João de Ruão).
Also impressive are the bird's-eye views of the city and surrounding landscape from the rooftop terrace, accessible by way of a narrow spiral staircase.