What are facts about the contribution of ancient Rome?

Rome developed the arch which was capable of supporting weight more efficiently than the columns used by the Greeks, Egyptians, and others. They also extended the arch into a tunnel-like structure called the vault, and they ran the arch in a circle called the dome. These architectural innovations have long outlived the Romans, and the Jefferson Memorial in Washington DC is a copy of a domed temple in Rome called the Pantheon, built by Marcus Agrippa. The arch was also used for bridges and aqueducts. Rather than rely on huge blocks of stone which had to be quarried and transported from a great distance, the Romans developed a kind of instant stone; concrete, which we still use today. The Romans also had hydraulic concrete which hardened when wet. The infamous Roman puppet Herod the Great built a port city called Caesaria where no natural harbor existed. Forms were erected in the water, and the hydraulic concrete was poured into them. Caesaria was similar to the two "Mulberry" harbors used at Normandy in June 1944, except that these were made of preformed concrete cassions which were towed into place and sunk. Although constructed with concrete reinforced by steel I-beam, the modern circular sports stadium was certainly inspired by the Roman amphitheaters which were the most difficult to build of all Roman architecture.