Under Hadrian Rome attained its greatest splendor, and after him, there was a progressive decline in the arts, since the public taste was corrupted. Still successive emperors continued to adorn the city. Marcus Aurelius, the wisest and best of all the emperors, erected a column similar to that of Trajan, to represent his wars with the Germanic tribes, and this still remains; he also built a triumphal arch. Septimius Severus erected the most beautiful of the triumphal arches, of which the Arc de Triumph in Paris is an imitation; and Caracalla built one of the greatest of the Roman baths, which, with the porticoes which surrounded it, formed a square of eleven hundred feet on each side--so enormous were these structures of luxury and utility, designed not only for the people as a sanitary measure, but for places of gymnastic exercises, popular lectures, and the disputations of philosophers. The Pantheon was merely an entrance to the baths of Agrippa. The baths of Trajan covered an area nearly as great. But those of Caracalla surpassed them all in magnificence. Nothing was more striking to a traveler than the painted corridors, the arched ceilings, the variegated columns, the elaborate mosaic pavements, the immortal statues, and the exquisite paintings which ornamented these places of luxury and pleasure. From amid their ruins have been dug out the most priceless of the statues which ornament the museums of Italy--the Farnese Hercules, the colossal Florae, the Torso Farnese, the Torso Belvidere, the Atreus and Thyestes, the Laocoon, beside granite and basaltic vases beautifully polished, cameos, bronzes, medals, and other valuable relics of ancient art. To supply these baths new aqueducts were built, and the treasures of the empire expended. Those subsequently erected by Diocletian contained three thousand two hundred marble seats, and the main hall now forms one of the most splendid of the Roman churches. [Sidenote: Temples and Palaces.] [Sidenote: General aspect of the city.] [Sidenote: What a traveler would see in a walk.] [Sidenote: The Via Sacra.] [Sidenote: The Velabrum.] [Sidenote: The Fora.] [Sidenote: View from the summit of the Capitoline Hill.] [Sidenote: Gardens of Lucullus.] [Sidenote: The Subura.] [Sidenote: Circus Maximus.] [Sidenote: View of Rome from the Capitol.]