Mount Parnes, and Ægaleos in the distance; but it resembles more truly Rome, sitting on a cluster of hills, with an ample plain for future expansion, with hills near and mountains distant, the Janiculum answering to Olivet, and the Apennines to the Heights of Moab.[72] To reconcile this passage with the topographical facts as they appear to every observer, some have pointed to the white mountains of Tîh on the south, to the wall-like ridge of Moab on the east, and to the rugged summits of Lebanon on the north; but it is simpler and more natural to suppose that the Psalmist had in his mind Olivet, the Mount of Corruption, and the Hill of Evil Council, rising from the two valleys which, like some deep moat, circumvallate the city on the east, south, and west; referring not so much to the height of the hills above the level of the city, as to their height from their valley beds, in which their everlasting bases rest. But on the north there is no such natural obstruction to impede the advance of an enemy. The ground rises gently to the summit of Scopus, which is a western projection of the Olivet ridge, a mile distant from the town, and which gradually disappears toward the west. To strengthen by art what nature had left defenseless, the celebrated tower of Psephinus was erected at the northwest corner of the ancient wall, which, being 70 cubits high, was not only a “tower of strength,” but also afforded from its top at sunrise a view of Arabia and of the sea. Less than two miles to the northwest from Jerusalem are two slight depressions, separated by a rocky swell three quarters of a mile in width. The one on the north is the head of the Valley of the Kidron. At first a gentle depression, it runs eastward a mile and a half; then turning suddenly southward, it contracts and deepens, and becoming precipitous in its course, sweeps round the bases of Bezetha, Moriah, and Ophel, joining the Vale of Hinnom at the beautiful Gardens of Siloam. Varying in depth and breadth, it is seventy-five feet deep at the northeast corner of the city, twenty-five deeper opposite St. Stephen’s Gate, and reaches its greatest depth of 150 feet at the southeast angle of the Temple area. Varying in breadth from a hundred to a thousand feet, it is narrowest opposite the southeast corner of the town, and has its greatest breadth between Moriah and Olivet, on a line drawn from the Golden Gate.