The pretty steep declivity of that height towards the gulf and its numerous rocks and shallows gave natural strength to the side of the city next to the gulf, and a simple circumvallation was sufficient there.

On the wall along the west or landward side, on the other hand, where nature afforded no protection, every appliance within the power of the art of fortification in those times was expended.

It consisted, as its recently discovered remains exactly tallying with the description of Polybius have shown, of an outer wall 6 1/2 feet thick and immense casemates attached to it behind, probably along its whole extent; these were separated from the outer wall by a covered way 6 feet broad, and had a depth of 14 feet, exclusive of the front and back walls, each of which was fully 3 feet broad.( 9) This enormous wall, composed throughout of large hewn blocks, rose in two stories, exclusive of the battlements and the huge towers four stories high, to a height of 45 feet,( 10) and furnished in the lower range of the casemates stables and provender-stores for 300 elephants, in the upper range stalls for horses, magazines, and barracks.( 11) The citadel-hill, the Byrsa (Syriac, birtha = citadel), a comparatively considerable rock having a height of 188 feet and at its base a circumference of fully 2000 double paces,( 12) was joined to this wall at its southern end, just as the rock-wall of the Capitol was joined to the city-wall of Rome.

Its summit bore the huge temple of the God of Healing, resting on a basement of sixty steps.

The south side of the city was washed partly by the shallow lake of Tunes towards the south-west, which was separated almost wholly from the gulf by a narrow and low tongue of land running southwards from the Carthaginian peninsula,( 13) partly by the open gulf towards the south-east.
At this last spot was situated the double harbour of the city, a work of human hands; the outer or commercial harbour, a longish rectangle with the narrow end turned to the sea, from whose entrance, only 70 feet wide, broad quays stretched along the water on both sides, and the inner circular war-harbour, the Cothon,( 14) with the island containing the admiral's house in the middle, which was approached through the outer harbour.