Final answer:
The construction of Roman aqueducts was made possible primarily by the use of arches, an architectural innovation that allowed for the support of immense weight and span across large gaps.
Step-by-step explanation:
The construction of the Roman aqueducts was made possible through the use of arches. These architectural features allowed the Romans to construct aqueducts that could span wide distances and support the weight of the water being transported. The arches were composed of wedge-shaped stones known as voussoirs, with a central keystone that locked them in place. Arches are very efficient at redistributing weight, funneling the forces from the top of the arch down to its base, which is why they could support the immense weight of these structures.
Roman engineers were also known for their use of concrete, which, when combined with the arch, gave rise to other structures such as vaults and domes. These developments further exemplified the Romans' innovative spirit in architecture and their skill in engineering. While aqueducts often feature the most visible use of arches, these structural elements were widely employed throughout various Roman buildings and infrastructure.