Not far from Porta Marzia, the majestic Roman Nicchioni overlook Piazza del Mercato Vecchio. The structure dates back between the late Republican and the early Augustan ages, consists of four big apses made of travertine blocks and provided with a Doric decorative cornice on top. The triglyphs and the metopes are adorned with bas-reliefs sculpting arms and human faces. The structure might have been a terrace wall supporting the above hill side or an elevated road, now disappeared, which could allow to access the square on the upper level.
According to Medieval tradition, instead, the Nicchioni would be the remains of an abandoned temple dedicated to Apollo.