Roman Bridge over the Guadiana, Mérida · Wikimedia Commons

Pons Emeritensis

Roman Bridge of Mérida

BridgeLusitania · Mérida, SpainBuilt 25 BCE

About

Augustus's veterans founded Emerita Augusta in 25 BCE as a retirement colony for soldiers of the Cantabrian Wars, and builders soon raised this bridge across the Guadiana to link the new Lusitanian capital to the southern road network. Including its approaches it ran nearly 790 meters on more than 60 granite arches, making it one of the longest bridges the Romans ever built and still the longest surviving bridge from the ancient world today. Trajan himself was born a few days' ride away at Italica, and by his reign the bridge had already carried Lusitania's capital's traffic for well over a century. The dams at Proserpina and Cornalvo that fed Emerita Augusta's own aqueducts stood just outside the city this bridge served.

What happened here

Piers are set on cofferdams — a ring of driven piles, pumped dry, filled with concrete that sets under water. They are built with a cutwater pointing upstream to split the current and the ice. The span above may be stone arches or timber on stone, and timber is not a poor relation: it is cheaper, faster, and replaceable. Roads approach on an embankment so the crossing stays level. Tolls are common, shrines at either end are usual, and the inscription names whoever paid. Floods are the enemy; a bridge is inspected after every big one, and the scour around the piers is packed with rubble. A bridge fixes a town's position for a thousand years, which is why so many are still standing.