The hook
A vast former mosque whose interior is a hypnotic forest of red-and-white striped double arches, with an entire Christian cathedral built into the middle of it centuries later.
01Why it's worth it
When Córdoba was the capital of Muslim Spain and one of the largest cities in the world, it built this mosque, and its prayer hall is unlike anything else: hundreds of columns carrying tiers of horseshoe arches banded in red brick and white stone, repeating in every direction until the space feels endless. After the Christian conquest the building was kept and, remarkably, a full Renaissance cathedral was raised right in its centre, choir and all, so you walk from the low arched forest straight into a soaring nave. The result is one building holding two religions in visible tension, which is the whole point and the whole controversy. Around it, the old Jewish quarter's white lanes and flower-filled courtyards make the setting; in early May the city throws open its private patios.
02How to experience it
Go at opening, or on the days with a free early slot, to walk the arches before the groups arrive and the light is still low through the doorways. Give the old town an hour for the patios and the synagogue, and cross the Roman bridge for the view back to the mosque at dusk.
From the locals
Andalusians rate the city among the region's best — "Andalucía has some of the most beautiful cities: Cádiz, Sevilla, Granada, Córdoba, Málaga… the downtown areas are very well kept and the historical sites are amazing" — but the advice that recurs is about pace. Told of a plan taking in Granada, Córdoba and Sevilla in a week from Madrid, one Spaniard pushed back hard: "you're pushing it… unless you want to experience Spain primarily out of the window of a car or train." Pick two, not three.