XIX. View in the Substructure, with the mouth of the Great Drain, and the iron grating and the grooves of the sluice-gate. XX. Portion of the Superstructure in the principal gallery. XXI. View in the Upper Part, with the aperture from which a travertine pier has been carried away. XXII. The Graffiti: A. and B. Athletes; C. A hunt of wild beasts. XXIII. A Graffito of the framework of the netting or gilt wire on the _podium_. XXIV. Representations of the Colosseum on Coins. XXV. Diagrams of the Coins. XXVI. A Roman Galley on a Cradle. XXVII. I. Amphitheatre at Capua. II. Amphitheatre at Pompeii, from a fresco of the first century. XXVIII. Amphitheatre at Capua—Perspective View and Details. XXIX. Amphitheatre at Capua—Details. XXX. Amphitheatre at Capua—Plan of Substructures and Superstructures. XXXI. Amphitheatre at Verona—A. Exterior. B. Interior. XXXII. Amphitheatre at Pozzuoli—Arena. XXXIII. Amphitheatre at Pozzuoli—Plan. XXXIV. Amphitheatre at Pozzuoli—Views and Section. XXXV. Amphitheatre at Pozzuoli—Views in the Interior, subterranean part. XXXVI. Colosseum—Plan of the Great Drain. THE FLAVIAN AMPHITHEATRE, COMMONLY CALLED THE COLOSSEUM. The importance of the great excavations made in 1874 and 1875 in this colossal building, and the evidence obtained by them for the history of the fabric, can hardly be overrated. It is now evident that the substructures under the level of the base of the _podium_ are (when not rebuilt) the earliest part of it, and considerably earlier than the time of the Flavian Emperors, who built the magnificent front and corridors around a theatre previously existing on that site. This great amphitheatre is indeed enumerated by Suetonius[23] among the works of Vespasian, and he adds that an amphitheatre in the centre of Rome had been projected by Augustus. But he does not say that it was then begun, and it seems evident that it was in use in the time of Nero in connection with his great golden house, and was partly built by him, but the exterior left unfinished. It contained the _stagna_, or _stagnum navale_, called also _Vetus Naumachia_, made at a still earlier period on the same site, which was called the old _naumachia_, when Augustus made new and larger ones in the Trastevere. It also contained his gymnasium on the boarded floor, or _arena_, of the theatre, over the _stagna maritima_, or canals for the sham naval fights. We know nothing certain as to the exact date of the commencement, but the building was continued during the reign of Vespasian and till the second year of Titus, namely A.D. 80, when it was dedicated. There is no evidence to prove that it was _commenced_ even under Nero. Pliny gives an account of a wooden amphitheatre built by Statilius Taurus, which was in the Campus Martius; he says[24] that