Although this did not apply to the Subura slums, which were still as rickety and fire-prone as ever, he did leave a mark on the monumental topography of the centre and of the Campus Martius, with the Ara Pacis (Altar of Peace) and monumental sundial, whose central gnomon was an obelisk taken from Egypt. The relief sculptures decorating the Ara Pacis visually augmented the written record of Augustus's triumphs in the "Res Gestae". Its reliefs depicted the imperial pageants of the praetorians, the Vestals, and the citizenry of Rome.