At Via Talamone the Walls change direction. Originally the Antoninian aqueduct ran along this point, an offshoot of the Aqua Marcia built by Caracalla [Marcus Aurelius Antoninus] to bring water to his Baths, the construction of which began in 212 AD.
The terrain was higher than today and the aqueduct, for a section underground, continued from here on arches and crossed the Via Appia [Appian Way] with the so-called “Arch of Drusus”, and then reached the Baths. With the construction of the Aurelian Walls, the Aqua Marcia canal crossed the Walls and was incorporated into this tower. In the early 19th century, the ground was lowered by about 4 metres in order to lay out the road along the exterior of the entire defensive wall circuit. The arches of the aqueduct were destroyed, and its speco (conduit) was left in view at the base of the tower, attached to a structure of small squared Peperino blocks, possibly a piscina limaria, a water purification cistern.
