Augusta Emerita: Roman city in western Spain, modern Mérida, capital of the province of Lusitania.
The first-century bridge across the Guadiana River, made of concrete and clad with dressed ashlars, has often been repaired. With sixty arches and a length of almost eight hundred meter (792 to be precise), Mérida's Roman bridge is the longest in Spain.
It rises about twelve meter above the average water level. However, the Guadiana sometimes floods, and the small arches inside the piers are thereto enable high water to pass along, and take away some pressure from the bridge.