The Cloaca Maxima was vitally important to the creation of Rome. The Cloaca Maxima was built around the 6th century BC and predates the Roman Empire. During the Imperial period the drain and the sewer system was maintained by Marcus Agrippa. Its engineering is brilliant because it drains the water that floods over from the Tiber River creating a solid foundation for the city to be built on. If the drain didn't exist neither would the Roman Forum.