Ciudadela

The walls and bulwarks of the grand fortified citadel, the star-shaped Ciudadela, were built between 1571 and 1645 under the direction of King Felipe II. They're considered one of the best examples of military architecture from the Spanish Renaissance. The former moats and bastions have become a setting for artists to display their works in the evenings from 6pm to 8.30pm Tuesday to Friday, noon to 2pm and 6pm to 8.30pm Saturday, and noon to 2pm Sunday.