Answer:
Barrel vaults
Concrete
Windows that let in light.
Step-by-step explanation:
The architecture of Ancient Rome is an important legacy of Roman civilization to the western world. Although sometimes considered to be derived from Greek architecture, it differed in its own characteristics. Barrel vaults, concrete (or the way Romans used it) and windows that let in light were some of the differences we can find between the Roman and Greek architecture. In this way, the Romans introduced new materials in architecture, such as the use of cement, as well as new techniques. The arch, unknown to the Greeks, was an innovation of the Romans, used mainly in buildings designed to commemorate the great military victories.