The Alconétar Bridge (Spanish: "Puente de Alconétar"), also known as Puente de Mantible, was a Roman segmental arch bridge in the Extremadura region, Spain. The ancient structure, which featured flattened arches with a span-to-rise ratio of 4–5:1, is one of the earliest of its kind. Due to its design, it is assumed that the bridge was erected in the early 2nd century AD by the emperors Trajan or Hadrian, possibly under the guidance of Apollodorus of Damascus, the most famous architect of the time.