The Porta Palatina (named after an unidentified palace) is an exceptionally well-preserved Roman gate, built during the reign of Augustus. It is made of brick and has multiple portals for pedestrians and wheeled traffic. It is framed by two tall sixteen-sided watchtowers (each thirty metres or 98 feet high). The construction symbolised Roman presence on the shores of the Po River and the plain of Cisalpine, on the southern side of the Alps, in Italy.