The side of the city toward the isthmus was defended by a wall forty-five feet in height (Diodorus says sixty) and thirty-three in thickness, interrupted at intervals of two hundred yards by lofty towers; the “topless towers,” no doubt, for which the city was famous. The seemingly unnecessary thickness of these tremendous ramparts is explained by the fact that they were hollow and contained four floors of rooms or casemates. On the ground floor were stables for three hundred elephants; on the second, stalls for four thousand cavalry-horses, together with space for the storage of vast quantities of fodder; while in the two upper stories were quartered twenty-four thousand fighting-men, who had with them supplies sufficient to last through a siege of several years’ duration. This single landward wall was, in short, a great fortress, containing more men and animals than are comprised in two modern army divisions. Carthage within the walls—I am referring, of course, to the Punic city—consisted of three distinct districts. Atop of a small hill, six hundred feet in height, from which it dominated the entire city, stood a vast walled inclosure, half-citadel, half-temple, known as the Byrsa. From this, three broad thoroughfares and an imposing flight of marble steps led down to the Cothon, or military harbor, which lent its name to the entire mercantile quarter of the city. To the northward, climbing part way up the mountain slopes, lay the vast suburb of Megara, where the wealthy merchants had their villas.