The complex comprises a sequence of three functional spaces arranged in series along an axis parallel to the Tiber: the entrance plaza with the offices and library at the lower level; the transparent case of the Ara Pacis with the exhibition spaces; and the three-level building with the auditorium and cafeteria. Access to the museum is from Via Tomacelli and features a system of steps and ramps in polished travertine that gradually ascend to the level of the plaza. A fountain set against a wall and a rectangular pool with water jets delimit the space towards the Lungotevere, aligned with the large partition clad in slabs of quarry-hewn travertine, which continues above ground into the museum atrium.