Don't miss the extraordinarily powerful spectacle of the Puente Romano spanning the Río Guadiana. At 792m in length with 60 granite arches, it's one of the longest bridges built by the Romans. It was constructed in 25 BCE when Emerita Augusta (modern-day Mérida) was founded, and then partly restored in the 17th century. The 20th-century Puente Lusitania, a sleek suspension bridge designed by Santiago Calatrava, mirrors it to the northwest. The best Roman bridge views are from the Alcazaba's southwestern ramparts.