With the most striking exterior of any church in Porto, Ingreja de Santo Ildefonso has a facade covered with some 11,000 blue and white azulejo tiles. The church was completed in the 18th century, on the site of a previous chapel that dated to the Middle Ages. The exterior is the real attraction, with tiles that depict scenes from the Gospels and the life of Saint Ildefonso. Inside you'll find a raised altarpiece by the 18th-century Italian artist Nicolau Nasoni, gilded in gold. Far from a relic for tourists, the church holds a daily mass that's usually packed with locals.