Pliny says that Agrippa, in his ædileship, made no less than seven streams meet together underground in one main channel, with such a rapid current as to carry all before them that they met with in their passage. Sometimes when they are violently swoln with immoderate rains, they beat with excessive fury against the paving at the bottom and the sides. Sometimes in a flood the Tiber waters oppose them in their course; and then the two streams encounter with great fury; and yet the works preserve their ancient strength, without any sensible damage. Sometimes huge pieces of stone and timber, or such-like materials, are carried down the channel; and yet the fabric receives no detriment. Sometimes the ruin of whole buildings, destroyed by fire or other casualties, presses heavily upon the frame. Sometimes terrible earthquakes shake the very foundations, and yet they still continue impregnable. Such is the testimony of Pliny the Elder. The Cloaca Maxima still exists. At its outlet in the Tiber, it is said to be thirteen feet high, and as many in breadth. The ancients always regarded this work as a great wonder. Livy speaks of it in terms of admiration; and Pliny equally so; and Dionysius says that the sewers having been once so greatly neglected that sufficient passage was not afforded for the waters, it cost no less a sum than 225,000_l._ to put them in repair. The Pyramid of Cestius, one of the most ancient remains, is the only specimen of a pyramid in Rome. It was erected daring the republic, to the memory of Caius Cestius, one of the priests that provided feasts for the gods. It is of great size, being ninety-seven feet in the base, and one hundred and twenty-four in height; and was erected, according to the inscription, in three hundred and thirty days. This ancient monument remains entire[158]. It is formed, externally, of white marble. At each corner on the outside was a pillar, once surmounted with a statue. Its form is graceful, and its appearance very picturesque; supported on either side by the ancient wall of Rome, with their towers and galleries venerable in decay, half shaded by a few scattered trees; and, looking down upon a hundred humble tents interspersed in the neighbouring groves, it rises in lonely pomp, and seems to preside over these fields of silence and mortality.