As the Empire grew so did the capital. A total of 11 aqueducts were built to service Rome. And the population spread well beyond the circuit of the Servian Wall. As long as peace reigned, there was no problem. But as the Empire began to crumble, the need for a new wall became paramount, so the Aurelian Wall was built. The wall survived the fall of the Empire, the aqueducts did not. Lecture 2 of 2.