Opus lateritium-- { Pantheon Augustus. Bricks, 6 to foot { Prætorian Camp Tiberius. { Palace Caligula. Bricks, 8 to foot Aqueduct Nero. Bricks, 7 to foot Palace Domitian. Bricks, 6 to foot Temple of Venus and Rome Hadrian. Bricks, 7 to foot Nymphæum, on Palatine M. Aurelius. { Baths Caracalla. { Nymphæum Alexander { Severus. Bricks, 5 to foot { Walls of Rome Aurelian. { Thermæ Diocletian. { Basilica Constantine. Bricks and tufa { Circus of Maxentius 300 A.D. { House of Gregory 590 A.D. Opera Saracenesca S. Sisto Vecchio 1200 A.D. Opus Spicatum Herring-bone pavement. Opus Signinum Cement for reservoirs, etc. [Illustration: PLAN OF ANCIENT ROME] RAMBLE I. PIAZZA DEL POPOLO -- THE OBELISK -- S. MARIA DEL POPOLO -- THE CORSO -- S. LORENZO IN LUCINA -- POST OFFICE -- ENGLISH CHURCH -- COLUMN OF MARCUS AURELIUS -- MONTE CITORIO -- PARLIAMENT HOUSE -- OBELISK -- TEMPLE OF NEPTUNE -- S. MARIA IN VIA LATA -- THE SEPTA -- THE DORIA GALLERY -- TOMBS OF ATTIA CLAUDIA AND BIBULUS -- THE MAMERTINE PRISON -- THE FORUM OF JULIUS CÆSAR -- THE ROMAN FORUM AND ITS RUINS -- THE VIA SACRA -- TEMPLES OF ROMULUS, VENUS AND ROMA -- TEMPLE OF THE PENATES -- HOUSE OF JULIUS CÆSAR -- BASILICA OF CONSTANTINE -- S. FRANCISCA ROMANA -- THE PALATINE HILL AND THE PALACE OF THE CÆSARS -- ARCH OF TITUS -- THE TEMPLE OF THE SUN -- THE FORUM OF CUPID -- PEDESTAL OF NERO'S COLOSSUS -- META SUDANS -- ARCH OF CONSTANTINE -- THE COLOSSEUM. THE CENTRE OF ROME. THE PIAZZA DEL POPOLO