The modern Via Cassia, now as in antiquity the great arterial road up through the heart of south-eastern Etruria, after crossing the Fosso dell'Olgiata less than a kilometre to the west of the north-western gate of Veii, climbs steadily for about 7 km. to cross the Monti Sabatini, the line of extinct volcanic craters that runs eastwards from Lake Bracciano, forming a natural northern boundary to the Roman Campagna. After cutting through the southern crest of the crater of Baccano, with its magnificent views southwards and eastwards over Rome towards Tivoli, Palestrina and the Alban Hills, the road drops into the crater, skirts round the east side of the former lake, and climbs again to the far rim, before dropping once more into the head of the Treia basin, on its way to Monterosi and Sutri.
From this vantage-point a whole new landscape is spread out before one (pl. XLVII). To the west and north-west, the tangle of volcanic hills that forms the northern limit of the Monti Sabatini, rising at its highest point to the conical peak of Monte Rocca Romana (612 m.); beyond and to the right of those, past Monterosi and filling the whole of the north-western horizon, some 10–15 km. distant, the spreading bulk of Monte Cimino (1053 m.), with its characteristically volcanic, twin-peaked profile; to the north and north-east, the gently rolling woods and fields of the Faliscan plain, deceptively smooth, stretching away to the distant Tiber.