What was the contribution of the Romans to the development of architecture?

The Romans were the first civilization of the ancient world to build multi-storey residential buildings. Some buildings of a similar purpose in Rome rose 6 or more floors. They invented arched structures that made it possible to erect a structure of an unprecedented height. The Colosseum is a good example of this. And in addition, it was Roman architects who began to build public and palace buildings that clearly declare the greatness of the Roman Empire with their monumentality and incredibly rich decoration.