Mérida, world heritage city and the capital of Spain's Extremadura region, was once also capital of the Roman province of Lusitania (Emerita Augusta, founded 25 BC). It is still home to the most impressive and extensive Roman ruins in all Spain. The ruins lie speckled around town, often appearing in the most unlikely corners. Remains of the ancient city include the still-used Teatro Romano, which has a double tier of columns rising onstage and offers open-air theatre performances on summer's nights. The ancient Puente Romano, a 2,600 foot bridge spanning the Río Guadiana which adjoins the Alcazaba, a 9th-century Islamic fortress built over Roman walls. In Mérida there are two places you can't possibly miss: the Roman theatre and amphitheatre, and the National Museum of Roman Art.