Yemen is best known of all the provinces, and has been quite thoroughly explored by a score of intrepid travellers.[20] Most people, however, travelling in a P. and O. Steamer, calling at Aden for coal, remain in total ignorance of the fair highlands just beyond the dark hills that hide the horizon Yemen extends from Aden to Asir on the north and eastward into Hadramaut for an indefinite distance. On the earlier maps Arabia Felix stretched as far as Oman—a great mountainous region with a temperate climate. An Arabian author, describing Yemen as it was before the time of Mohammed, wrote: “Its inhabitants are all hale and strong, sickness is unknown, nor are there poisonous plants or animals; nor fools, nor blind people, and the women are ever young; the climate is like paradise and one wears the same garment summer and winter.” The massive rock promontory of volcanic basalt called Aden, has from time immemorial been the gateway and the stronghold for all Yemen. It is generally agreed that Ezekiel, the prophet, referred to Aden when he wrote. “Haran and Canneh and _Eden_, the merchants of Sheba, Asshur and Chilmad, were thy merchants.” The place was fortified and its wonderful rock cisterns were probably first constructed by the early Himyarites. A Christian church was erected at Aden by the embassy of the Emperor Constantius, A.D. 342, and Aden was for a long time in the hands of the Christian kings of Yemen. Then it fell a prey to the Abyssinians and next to the Persians, about the time when Mohammed was born. Albuquerque in 1513 with his Portuguese warriors laid siege to Aden for four days, but in spite of scaling-ladders and gunpowder could not take the town. The Mameluke Sultans of Egypt also failed to capture this fortress. In 1838 the English took it by storm and have held the place ever since. Aden is now a British settlement, a commercial-centre, a coaling-station and a fortress; the last most emphatically. All the latest improvements in engineering and artillery have been put to use in fortifying the place. The ride from Steamer-Point to “the crater” or from the telegraph-station to the “Crescent” gives one some idea of the vast amount of money and labor expended to shape this Gibraltar and make it impregnable from land and sea. The isthmus is guarded by massive lines of defence, strengthened by a broad ditch cut out of the solid rock; bastions, casements and tunnels all serve one purpose; batteries, towers, arsenals, magazines, barracks; mole-batteries toward the sea, mines in the harbor, obstruction piers and subservient works;—everything tells of military strength, and the town has always a warlike aspect in perfect accord with its forbidding physical geography.