The Alcántara Bridge (also known as Puente Trajan at Alcantara) is a Roman stone arch bridge built over the Tagus River at Alcántara, Spain between 104 and 106 CE by an order of the Roman Emperor Trajan in 98. It bears the inscription Pontem perpetui mansurum in saecula (I have built a bridge which will last forever) on the archway over the central pier.
The Alcántara Bridge has taken more damage from war than from the elements. The Moors destroyed the smallest arch on the left side in 1214. This was rebuilt in 1543 with stone from the original quarries. The second arch on the right side was destroyed by the Spanish to stop the Portuguese and was repaired in 1762 by Charles III, only to be blown up again in 1809 to stop the French. Temporary repairs made in 1819 were replaced in 1860 with mortared masonry