Old town, Gothic Quarter, beaches, Sagrada Familia, tappas and tappas, the Market, bistros, delis, charming narrow streets, parks, plazas, public transportation.
Phew. All good. Wonderful city to spend at least three days eating, 0snooping, absorbing, and learning. Oh yeah, and there's the good wine, as well. One of the most inexpensive big cities I've ever visited - particularly food and beverage.
