The Alcazar, that immense pile, once the residence of Moors, and subsequently of the kings of Spain, forms one corner of the city. The irregular and picturesque line of buildings, at least one half of them convents, each with its tower, and terrace, and hanging garden, stretches along the summit of the hill, towards the West; while strewing the sides of the steep acclivity, and mingled with the convent gardens, are seen the remains of the Roman walls that once entirely inclosed the city, and that even yet, are in many places nearly perfect. Withdrawing the eye from Toledo, and looking across the bridge, an elevated rocky mount presents itself, crowned with the ruins of a Moorish castle; and leaning on the parapet, and looking towards the South, the river is seen far below, flowing in a deep rocky channel, one of its banks being the hill upon which the city stands,--and the other, the North front of the Toledo mountains. The peculiar situation of Toledo is best understood from this point. The river Tagus, coming from the westward, flows directly towards the north-east corner of the city; and in place of continuing to flow in the same direction--by which it would leave the city and its hill upon the left,--it makes a sudden turn, sweeps behind the city and its hill, and in front of the Toledo mountains,--and after describing three parts of a circle, it re-appears at the opposite corner, and continues its course towards the west. The course of the Tagus is singular; the Sierra de Albarracin, where it rises, is no more than eighty miles from the Mediterranean, in a straight line across Valencia; but the Tagus, taking an opposite direction, runs a course of nearly six hundred miles to the Atlantic,--traversing the interior of Spain, passing into Portugal, and forming the glory and the riches of its capital. It would be no difficult matter, to render the Tagus navigable from Toledo to the sea, a distance of between four and five hundred miles; the passage was attempted in the winter of 1829, by a boat from Toledo, and succeeded, the boat having arrived safely at Lisbon; but this could not have been done at any other season; because in dry weather, the water is in many places almost wholly diverted from its natural channel, for the use of the mills that have been erected upon its banks.