The Plaza de España is a magnificently proportioned semi-circular space designed for the Ibero-American World's Fair of 1929. It's edged by buildings and tile patterns that blend a Deco sensibility with traditional techniques.
If it looks familiar, it may be because you've seen it acting as a backdrop in Star Wars II: Attack of the Clones.
At the Plaza's center is an impressive fountain, and edging the buildings are little moats that you cross over elegant bridges. Next to the Plaza is the Maria Luisa Park, with its orange trees and formal gardens. These days the buildings in the Plaza are used by the government.
One of the loveliest reasons to take a stroll in the Plaza de España is the tiled alcoves, each depicting the history of a different province of Spain. They're lovely in and of themselves, and they also attract visitors from all over Spain who want to be photographed against their home province's alcove; a great people-watching opportunity!
The Plaza de Espana is close to the river, in the Centro Histórico. If you walk south down the river from the Bullring or the Torre del Oro, you'll come across Maria Luisa Park. Head left to the park and you'll hit the Plaza.