Short answers, pulled from the story.
The 6th century BC marked the arrival of Etruscan engineers in Rome, bringing with them knowledge of bridge-building techniques that would eventually evolve into Roman engineering. Ancus Marcius ordered the construction of the Pons Sublicius over the Tiber River during this period.
By the 2nd century BC, stone replaced wood as the primary material for permanent bridges. Engineers began using volcanic ash mixed with lime and gypsum to create durable foundations while iron clamps held together the stones.
Italian scholar Vittorio Galliazzo identified 931 Roman bridges across 26 different countries including former Yugoslavia. Europe hosted 830 known structures while Asia contained 74 and Africa held 57.
Apollodorus of Damascus designed this structure featuring open-spandrel segmental arches resting on concrete piers. Trajan's Bridge over the Danube stood as the longest arch bridge for a thousand years in both overall length and individual span.
Local municipalities shared costs for building and repairing bridges through a system called opus pontis meaning bridge work. The Alcántara Bridge in Lusitania cost twelve local municipalities whose names appeared on inscriptions alongside their contributions.