The Igreja de Santa Maria de Marvila is arguably the most visually arresting church in Santarém. The interior is covered floor to ceiling with 17th-century azulejo tiles — blue-and-white painted ceramic panels depicting religious scenes and geometric patterns. The effect is overwhelming: the entire surface of the walls is tiled, and the quality of the panels is exceptional.
The church's origins are Manueline (early 16th century), and the exterior portal shows the characteristic twisting stone columns and maritime motifs of that style. But it's the tile interior that visitors remember. The church is open to visitors at specific hours — check locally as they vary. Even from the outside, the Manueline portal is worth a look.