We descended to the bottom, and from the little terrace, wet by the spray, and dark with overhanging rocks, looked up the "cavern of Neptune," a deep passage, through which the divided river rushes to meet the fall in the gulf. Then remounting to the top, we took mules to make the three miles' circuit of the glen, and see what are called the _Cascatelli_. No fairy-work could exceed the beauty of the little antique Sybil's temple perched on the top of the crag above the fall. As we rode round the other edge of the glen, it stood opposite us in all the beauty of its light and airy architecture; a thing that might be borne, "like Loretto's chapel, through the air," and seem no miracle. A mile farther on I began to recognize the features of the scene, at a most lovely point of view. It was the subject of one of Cole's landscapes, which I had seen in Florence; and I need not say to any one who knows the works of this admirable artist, that it was done with truth and taste.[3] The little town of Tivoli hangs on a jutting lap of a mountain, on the side of the ravine opposite to your point of view. From beneath its walls, as if its foundations were laid upon a river's fountains, bursts foaming water in some thirty different falls; and it seems to you as if the long declivities were that moment for the first time overflowed, for the currents go dashing under trees, and overleaping vines and shrubs, appearing and disappearing continually, till they all meet in the quiet bed of the river below. "_It was made by Bernini_," said the guide, as we stood gazing at it; and, odd as this information sounded, while wondering at a spectacle worthy of the happiest accident of nature, it will explain the phenomena of the place to you--the artist having turned a mountain river from its course, and leading it under the town of Tivoli, threw it over the sides of the precipitous hill upon which it stands. One of the streams appears from beneath the ruins of the "Villa of Mecænas," which topples over a precipice just below the town, looking over the campagna toward Rome--a situation worthy of the patron of the poets. We rode through the immense subterranean arches, which formed its court, in ascending the mountain again to the town. Near Tivoli is the ruined villa of Adrian, where was found the Venus de Medicis, and some other of the wonders of antique art. The sun had set, however, and the long campagna of twenty miles lay between us and Rome. We were compelled to leave it unseen. We entered the gates at nine o'clock, _unrobbed_--rather an unusual good fortune, we were told, for travellers after dark on that lonely waste. Perhaps our number deprived us of the romance.