The Church of São Francisco is Porto's Gothic masterpiece and contains what is arguably the most spectacular church interior in Portugal. The building dates from around 1425, and the Gothic exterior gives no warning of what is inside: the nave is covered almost entirely in gilt carved wood — walls, pillars, altarpieces, ceiling — in an 18th-century Baroque overlay that used an estimated 400 kilograms of gold.
The centrepiece is a carved "Tree of Jesse" altarpiece showing the genealogy of Christ, flanked by saints and angels in a chaos of gilded detail. It is the kind of interior that takes ten minutes just to adjust to. A museum attached to the church covers the Franciscan order's history in Porto and provides access to the medieval catacombs beneath the floor, where the bones of monks and benefactors lie undisturbed.