Roman aquaducts are a marvel of modern engineering and architecture. The ancient Romans constructed aquaducts to move water from springs in the mountains to the cities. The aquaducts could be up to 60 miles long and were composed of graceful arches. Many cities would not exist without these aquaducts. The water delivered by the aquaducts kept the cities of the Roman Empire clean. Otherwise, they would have been filthy because the sewers would overflow. Without clean water to remove the refuse, disease would have spread throughout the Roman empire.