It was girt with immense brick walls, 340 ft.

high and nearly 90 ft.

thick, and a broad deep moat full of water, and was entered through 100 gates; presumably we are intended to think of these gates as arranged symmetrically, 25 in each side.

From corner to corner the city was cut diagonally by the Euphrates, which thus halved it into two roughly equal triangles, and the river banks were fortified by brick defences--less formidable than the main outer walls--which ran along them from end to end of the city.

There was, too, an inner wall on the landward side.