In addition to the _enceinte_, the somewhat abrupt descent on the north- western side of Tunis is defended by three large forts built three centuries ago by the soldiers of Charles V. and his son, and called respectively Borj Manoubia, Borj Filfla, and Borj-el-Rebta. A lofty aqueduct constructed at the same time supplied them as well as the adjacent citadel with water from a distant spring, but it has now fallen into ruins, and is popularly described as of Roman origin. The Borj-el- Rebta is a splendid specimen of the science of fortification as understood by our forefathers. It is surrounded by a deep fosse, and bristles with useless cast-iron guns which serve to deceive the Tunisians since the Bey paid one of his loans ten years ago by the sale of all the brass and bronze cannon in the Regency. The city of Tunis is commanded by two hills in its immediate vicinity—viz., Sidi Bil Hassan, properly called Borj Sidi Ali Rais, to the south, and the Belvedere to the north. The fortress which crowns the former belongs to a period far anterior to that in which the Borj-el- Rebta was built, but its position is unrivalled. It dominates all the roads to Southern Tunis, and its elevation is some hundreds of feet above that of the Kasbah, or town citadel. Beyond it are two imposing looking sanctuaries, one of which is every Friday crowded with Tunisian ladies, who profess to find a cure for sterility in sliding down a rock on the slope of the hill upon which the _Zaouia_ in question is built. Belvedere was never fortified till the French appeared before Tunis in the early days of October 1881. The guns of Sidi Bil Hassan and the Borj-el-Rebta were sufficient to prevent its heights being occupied by the troops of the Dey of Algiers or the supporters of some rival to the beylical throne, the only enemies which Tunis has seen from its walls since the Spaniards evacuated it in 1574, and the friendly expanse of the “little sea” efficiently protected it from the artillery of Blake and the bombardments of half the fleets of Europe, which have repeatedly razed Goletta to the ground. The Belvedere hill was, however, the very first point occupied by the French troops, and was made the site of a strongly-intrenched camp, and fortified by earthworks.