Alconétar Bridge

The Alconétar Bridge (Puente de Mantible) was a Roman segmental arch bridge located in Extremadura, Spain. Built in the early 2nd century AD during the reigns of emperors Trajan or Hadrian, it featured flattened arches with a span-to-rise ratio of 4–5:1, making it one of the earliest examples of this innovative structural design. The bridge may have been constructed under the guidance of Apollodorus of Damascus, the era's most celebrated architect. Its engineering represented a significant advancement in Roman bridge construction techniques.