You will not be alarmed at the appearance of the walls, after what you have heard, for it is the celebrated Muro Torto that once propped the terraces of Domitian, and which, you already know, has seemed just as ready to fall these fourteen hundred years as it is to-day. This wall is said to be twenty-five feet thick, and it seems at least forty feet high. This height, however, rather exceeds that of the wall in general, which varies, perhaps, from twenty to thirty feet. We are next passing by that part of the city wall where the Villa Ludovisi Buon Compagni lies, _within_ the _enceinte_ of the city; and the gate just passed, and which is not used, is the Pincian. There is a tradition that Belisarius asked alms at this gate; but it is more probable that he caused it to be rebuilt. The little Gothic-looking tower that appears on the wall is in the garden of the Villa Paolina, so called from Pauline, the sister of Napoleon. This garden and its very handsome pavilion are now the property of the Prince of Musignano, her nephew, the eldest son of Lucien, a gentleman well known in America for his work on its birds. The gate beyond is the Porta Salara. Alaric entered the city at this point; and the Gauls, more remotely, penetrated by the Porta Collina, which was the counterpart of the present gate in the wall of Servius, though necessarily less advanced than this. Hannibal is also said to have manifested an intention to attack the town on this side, whence it is inferred it was the weak quarter. It is not probable the walls were less strong here than elsewhere; but the military advantages of attacking the place on this side are sufficiently apparent to the eye. The land both within and without the walls of Rome is higher here than any where else on this side of the Tiber. It is consequently drier and more healthy as an encampment, and, while equally easy to enter as any other quarter, offers great facilities to the assailant when gained. The gardens of Sallust lay just within this gate, and traces of the walls are still seen. The _agger_ of Servius Tullius, beneath which the vestal virgins who violated their vows were interred, was also within this gate. Traces of the former are still seen. This additional wall would seem to imply the danger the city ran on this particular side. The Pretorian Camp lay outside of this agger, but within a wall of its own.