at incomparable edifice, the Pantheon, the only
building of ancient Rome which still remains practically whole--of
baths, porticoes, and enclosed promenades.

[Illustration: FIG. 16.--SOME REMAINS OF THE CLAUDIAN AQUEDUCT.]

Away in the opposite direction stretched the Appian Way, and in the
year 64 the beautiful tomb of Caecilia Metella, which is so familiar
in picture, stood as perhaps the noblest among the multitude of
patrician tombs. The Apostle Paul certainly passed close by it on his
way from Puteoli. The aqueduct, of which so many arches still meet the
eye as you cross the Campagna, was the work of Nero's predecessor,
Claudius, and it still bears his name--the Aqua Claudia. Where now you
go out of the gate to St. Paul's Outside-the-Walls there stood--more
free and visible than now--that pyramid of Cestius, close to whose
shadow lie the graves of the English Shelley and Keats. There was no
gate at this spot in the days of Nero, for the great wall, of which so
many portions--more or less restored--are still conspicuous, had no
existence till a much later date, when the empire was already
tottering to its fall, and when Aurelian was driven to recognise that
the heart of the empire, after remaining secure for centuries, must at
last look to be assailed. There was, it is true, an inner wall of
ancient date (to be seen upon the plan) which had enclosed the "Seven
Hills" before Rome was mistress of more than her own small
environment. But the city had long ago overflowed this boundary, and
the newer quarters lay as open to the country as do our own modern
cities.

How far the suburbs stretched, or precisely how far Rome proper
extended, in the days of Nero, is no easy matter to decide. We shall
in all probability be near the mark if we accept the line of the later
wall of Aurelian as practically the limit of what might be included in
the "Metropolitan Area." The total circumference of the whole city
would be about twelve English miles, a circuit which fell somewhat
short of that of Alexandria and probably of Antioch, although in
actual importance these cities took but the second and third rank
respectively.

Some parts within this line were thickly inhabited, in some the houses
must have been but sparse. Particularly along the upper slopes of the
hills--of the Pincian, Quirinal, Esquiline, Caelian, and
Aventine--were the spacious houses and gardens of the wealthy. The
Palatine was almost, though not completely, mo