Puente Romano sobre el Guadiana Monument · Mérida, Tierra de Mérida - Vegas Bajas, Badajoz At 792 meters long and resting on a central islet in the river, it is one of the longest surviving Roman bridges. It still spans the Guadiana next to Mérida's historic center. Photo: Ardo Beltz (CC BY-SA 3.0) What to see and do in Mérida