The simple arch (barrel arch) was invented by the Etruscans. The Romans developed a more complex arch, the vaulted arch. The vaulted arch, combined with the development of a t
…ype of concrete which was much superior than that of other civilisations, facilitated the construction of large scale building and bigger bridges. Roman bridges crossed much wider rivers and valleys and much deeper valleys. In the case of deep valleys, two or three rows of arches were built on top on each other to make the bridge taller. Roman concrete also set underwater and was used to build much bigger docks for ports. Concrete also made it possible to build much bigger and sophisticated domes compared to those of other civilisations. The the aqueducts were another very important innovation. (MORE) 
