The only conclusion which it seems possible to draw from the conflicting testimony is that the numbers were either rough guesses made by very unskilful travellers, or else were (in most cases) intentional exaggerations palmed upon them by the native ciceroni.

Still the broad facts remain--first, that the walls enclosed an enormous space, which was very partially occupied by buildings; secondly, that they were of great and unusual thickness; and thirdly, that they were of a vast height--seventy or eighty feet at least in the time of Alexander, after the wear and tear of centuries and the violence of at least three conquerors.
The general character of the construction is open to but little doubt.
The wall was made of bricks, either baked in kilns, or (more probably) dried in the sun, and laid in a cement of bitumen, with occasional layers of reeds between the courses.

Externally it was protected by a wide and deep moat.

On the summit were low towers, rising above the wall to the height of some ten or fifteen feet, and probably serving as guardrooms for the defenders.

These towers are said to have been 250 in number; they were least numerous on the western face of the city, where the wall ran along the marshes.