But the remains of Carnak, about one mile and a quarter lower down the river, are still more wonderful than Luxor: one of the buildings is probably the temple of Ammon, which we know from Diodoius was on this side of the river. An irregular avenue of sphinxes, considerably more than a mile in length (about 6,560 feet), connected the northern entrance of the temple of Luxor with it; but this was only one of several proud approaches to perhaps the largest assemblage of buildings that ever was erected. For a minute description of Carnak we must refer to the plans in the great French work, and to Dr. Richardson's and Mr. Hamilton's accounts. The irregularities in the structure and approaches of this building show that the various parts of it were raised at different periods, for indeed it would have been impossible for any one sovereign to have completed such a monument in his life-time; and we know, also, that the great temple at Memphis received numerous additions during a long succession of ages. Some parts, both of this temple and of the larger building at Carnak (sometimes called a palace), have been constructed out of the materials of earlier buildings, as we see from blocks of stone being occasionally placed with inverted hieroglyphics. It is impossible without good drawings and very long descriptions, to give anything like an adequate idea of the enormous remains of Carnak, among which we find a hall whose roof of flat stones is sustained by more than 130 pillars, some 26 feet, and others as much as 34 feet, in circumference. The remains on the western side of the river are, perhaps, more interesting than those on the east. That nearly all the monuments of Thebes belong to a period anterior to the Persian conquest, B.C. 525, and that among them we must look for the oldest and most genuine specimens of Egyptian art, is clear, both from the character of the monuments themselves and from historical records; nor is this conviction weakened by finding the name of Alexander twice on part of the buildings at Carnak, which will prove no more than that a chamber might have been added to the temple and inscribed with his name; or that it was not unusual for the priests to flatter conquerors or conquerors' deputies by carving on stone the name of their new master. Thebes was the centre of Egyptian power and commerce, probably long before Memphis grew into importance, or before the Delta was made suitable to the purposes of husbandry by the cutting of canals and the raising of embankments.