* Granite: The bridge's piers and arches are constructed from large, precisely-cut blocks of granite, which was quarried locally. The granite is extremely durable, and has shown very little deterioration in the 2000 years since the bridge was built.
* Concrete: The bridge's vaults are made from a combination of concrete and rubble, which was poured over the granite framework. The concrete is made from a mixture of lime, pozzolana, and sand, and is very strong and durable.
* Iron: Iron clamps and dowels were used to secure the granite blocks and concrete together. The iron is of a high quality, and has also resisted corrosion over time.
* Lead: Lead was used to seal the joints between the granite blocks, creating a waterproof seal. The lead has also shown very little deterioration over time.
The Roman Bridge at Alcántara is a remarkable example of Roman engineering and architecture, and the materials used in its construction are a testament to the durability of Roman structures.