The town was situated on rising ground less than a mile from the foot of Vesuvius. This eminence is itself due to an outflow of lava from that mountain, during an eruption in prehistoric times, for we know that Vesuvius had been quiescent ever since the Greek settlements in this part of Italy.
The area occupied by the ancient city was of an irregular oval form, and about 2 m. in circumference. It was surrounded by a wall, which is still preserved for more than two-thirds of its ex tent, but no traces of this are found on the side towards the sea, and there is no doubt that on this side it had been already de molished in ancient times, so as to give room for the free ex tension of houses and other buildings in that direction. It con sisted of two parallel stone walls with buttresses, about 15 f t. apart and 28 in. thick, the intervening space being filled with earth, and there being an embankment on the inner side. These walls are strengthened at intervals by numerous towers, occupy ing the full width of the wall. They appear to have been added at a later period, probably that of the Social War. Similar evi dences of the addition of subsequent defences are to be traced also in the case of the gates, of which five have been cleared, while at least one (and perhaps three) more are unexcavated.
The general plan of the town is very regular, the streets being generally straight, and crossing one another at right angles or nearly so. But exceptions are found in the south-west corner, where a small irregular group of streets represents the original Oscan settlement, and on the north-west in the street leading from the Porta Ercolanese (gate of Herculaneum) to the forum, which, though it must have been one of the principal thoroughfares in the city, was crooked and irregular, as well as very narrow, in places not exceeding 12 to 14 ft. in width. Another exceution is to be found in the Strada Stabiana (Stabian Street) or Cardo, which, owing to the existence of a natural depression which affects also the line of the street just east of it, is not parallel to the other north and south streets. The other main streets are in some cases broader, but rarely exceed 20 ft. in width, and the broadest is about 32 ft., while the back streets run ning parallel to the main lines are only about 14 ft. (the standard width of a Roman highroad). They are uniformly paved with large polygonal blocks of hard basaltic lava, fitted very closely together, though now in many cases marked with deep ruts from the passage of vehicles in ancient times. They are also in all
cases bordered by raised footways on both sides, paved in a similar manner; and for the convenience of foot-passengers, these are connected from place to place by stepping-stones raised above the level of the carriage-way. The careful investigation in recent years of the buildings in the eastern portion of the Strada dell' Abbondanza has shown that previous conceptions of the appear ance of the exterior of the houses were entirely erroneous. The upper stories were diversified by balconies, open loggias, colon nades, etc., while the lower portions of the facades were painted, often with scenes of considerable interest. The streets were also diversified by fountains, small water-towers and shrines.
The first-mentioned of the two principal streets was crossed, a little before it reached the forum, by the street which led directly to the gate of Nola (Strada delle Terme, della Fortuna, and di Nola). Parallel to this last to the south is a street which runs from the Porta Marina through the forum, and then, with a slight turn, to the Sarno gate, thus traversing the whole area of the city from east to west (Via Marina, Strada dell' Abbondanza, Strada dei Diadumeni). These two east and west streets are the two decumani.
The population of Pompeii was mixed; both Oscan and Greek inscriptions are still found up to the last, and evidences of the presence of Jews are not lacking—such are a wall-painting, prob ably representing the Judgment of Solomon, and a scratched in scription on a wall, "Sodoma, Gomora." From the number of skeletons discovered, about 2,000 persons may have perished in the city itself in the eruption of A.D. 79.
The whole portion of the city which lies to the west of the Strada Stabiana, towards the forum and the sea, has been com pletely excavated. It is over one-half of the whole extent, and that the most important portion, inasmuch as it includes the forum, with the temples and public buildings adjacent to it, the thermae, theatres, etc. The greater part of that on the other side of the Strada Stabiana remains still unexplored, with the exception of the amphitheatre, a small space in its immediate neighbourhood and the buildings on each side of the Strada dell' Abbondanza and the Strada di Nola.