CLOACÆ, in Antiquity, the common sewers of Rome, to carry off the dirt and soil of the city into the Tiber; justly reckoned amongst the grand works of the Romans. The first common sewer, called Cloaca Maxima, was built by Tarquinius (some say Priscus, others Superbus), of huge blocks of stone joined together without any cement, in the manner of the edifices of those early times, consisting of three rows of arches, one above another, which at length conjoined and united together, measuring in the clear eighteen palms in height, and as many in width. Under these arches people rowed in boats, which caused Pliny say that the city was suspended in air, and that they sailed beneath the houses. Under these arches also were ways through which carts loaded with hay could pass with ease. This Cloaca commenced in the Forum Romanum, measured 300 paces in length, and emptied itself between the temple of Vesta and the Pons Senatorius. There were as many principal sewers as there were hills. Pliny infers their firmness and strength from their standing during so many ages the shock of earthquakes, the fall of houses, and the vast load and weights moved over them.