Gothic Quarter (Barri Gotic)

This is the oldest part of the city, a knot of narrow medieval streets sitting on Roman foundations. The obvious stops are the 14th-century cathedral, Placa Reial with its Gaudi lampposts and the Roman columns tucked inside a courtyard on Carrer Paradis, which you will walk past twice before you find the door. Wandering costs nothing. A walking tour is the one thing I would pay for here, because 2,000 years of city built on top of itself is not something a street explains by itself. There are tapas bars on every block, and the ones on the streets nobody photographs are usually cheaper.