Mezquita-Catedral de Córdoba
You step from bright Andalusian sun into sudden cool, and your eyes adjust. Then the columns emerge — 856 of them, jasper and marble, holding up a canopy of red-and-white horseshoe arches that recedes further than the building seems to allow. A Renaissance cathedral was inserted into the heart of the prayer hall in 1523, a collision that still feels unresolved and is all the more extraordinary for it. A UNESCO World Heritage Site that rewards two hours minimum, and repays a guided tour with 1,300 years of layered history made legible.