Aqua Claudia
Just a few traces of Nero's Palatine extension remain (E from the Palatine hill). The Porta Capena is clearly indicated (beyond the axis of the Circus Maximus); parallel to the Murus Servii was the Aqua Appia conduit. The Porta Capena was also the start of the Via Appia. (R. Lanciani: Forma Urbis Roma 35 Circus Maximus)