This road is the worst kept, the least interesting, and the most frequented out of Rome. The new tramway is now open, so it is more come-at-able than hitherto. Leaving the cemetery, we soon pass the Florence railway; then a bridge over the Ulmanus stream. The farm on the right, inside the gateway, is upon the site of the Villa of Regulus (Martial, i. 13). At the first mile was the monument of Pallas (Pliny younger, vii. 29; viii. 6). We soon cross the Anio by the modern bridge: the old one, Ponte Mammolo, can be seen to the right; it took its name from Mammæa, the mother of Alexander Severus, who repaired it. In these meadows Hannibal had his first camp (see page 288). Beyond, we pass along the modern causeway over the meadows where his second camp was, by the Tutia, which stream we cross. We now pass some of the old pavement, and upon the left CASTEL ARCIONE, a medieval castle belonging to a family of that name; destroyed by the S. P. Q. T., it having become a stronghold for brigands. The calciferous lake of Tartarus formerly existed, just beyond, but is now dried up. Near by a sulphurous odour indicates the proximity of the AQUÆ ALBULÆ, baths often frequented in ancient times. A channel, constructed by Cardinal Este, draws off the water from these sulphurous lakes to the Tiber. The bath-house was erected in 1880, and the water is beneficial for skin diseases. [Illustration: PLAN OF TIVOLI. 1 _Via della Sibilla_ 2 _Ponte Gregoriano_ 3 _Porta St. Angelo_ 4 _Grand Falls_ 5 _Glen & Falls_ 6 _Temples of Vesta & Sibyl_ 7 _Temple of Hercules_ 8 _Cascade_ 9 _Cascades_ 10 _Villa S. Antonio_] In the vicinity are the quarries of travertine--so called from the stone taking the ancient name _Tiburtians_--which have yielded the materials for building both ancient and modern Rome, the Colosseum, and S. Peter's. _Three miles from Tivoli we cross the picturesque_ PONTE LUCANO, which spans the Anio. Near by is the solid and magnificent Tomb of the Plautii, similar to that of Cecilia Metella. The upper part has been repaired in medieval times, that it might serve as a fortress. Erected, 1 B.C., by M. Plautius Silvanus for himself, Lartia his wife, and Urgularicus his child. The inscription tells us that one of his descendants served in Britain, and died A.D. 76. _A little beyond, a road turns off to the right, leading to Hadrian's Villa, which had better be visited in returning._ _First visit the glen at Tivoli, then take the road round to see the small falls passing over the Ponte dell' Acquoria. Turn to the right. This brings us into the main road below the town. A short distance down we turn off to Hadrian's Villa; or, instead of turning to the right after passing the bridge, the road to the left leads past the Tempio della Tosse up to the Villa d'Este._ TIVOLI. _Donkey for excursion to the Falls, one and a half lira; guide_ (_not necessary_), _one franc._