The whole circuit of Constantinople, however, calculated at somewhat more than twelve miles, present, even to diligent research[152], very few remains of antiquity. The truth is, the Turks have availed themselves of the marbles and fragments of the Greeks in the construction of their own public edifices; and the antiquities of Constantinople are re-produced to the eye under entirely different forms and constructions, in the mosques and minarets, the fountains and cemeteries of the Osmandys. Many a beautiful work, of the ancient Greek chisel, has thus been embedded in a wall, or cut down and defaced to make a Turkish tombstone; and many an edifice, constructed in accordance with the pure styles of architecture, has been levelled and used as a quarry. But still, it must be confessed that some of the Turkish buildings, and more particularly some of the imperial mosques which have risen in their places, are distinguished by grandeur and beauty. Of these imperial mosques there are fourteen, each lofty, and magnificent in its general dimensions, and built from base to dome with excellent and enduring materials; chiefly of white marble, tinged with grey. Besides these, there are sixty ordinary mosques, varying in size and beauty, but all considerable edifices; and then two hundred and more inferior mosques and messdgids[153]. The walls of Byzantium[154] were built of large square stones, so joined as, apparently, to form one single block. They were much loftier on the land side than towards the water, being naturally defended by the waves, and in some places by the rocks they are built on, which project into the sea. They were of Cyclopian structure[155]; and of the workmanship, from what Herodian has said of them, the masonry was greatly superior to any of the workmanship now visible in the fortifications. It was surrounded by a wall, made of such immense quadrangular masses of stone, and so skilfully adjusted, that the marvellous masonry, instead of disclosing to view the separate parts of which it consisted, seemed like one entire mass. "The very ruins," says Herodian, "show the wonderful skill, not only of the persons who built it, but of those, also, by whom it was dismantled." The wall of Theodosius begins at the castle of Seven Towers, whence it traverses the whole western side of the city. This is the only part of the general wall of the city worth seeing. It is flanked into a double row of mural towers, and defended by a fosse about eight yards wide. The same promiscuous mixture of the works of ancient art--columns, inscriptions, bas-reliefs, &c.--seen in the walls of all the Greek cities, is here remarkably conspicuous. But the ivy-mantled towers, and the great height of this wall, added to its crumbling ruinous state, give it a picturesque appearance, exhibited by no other city in the Levant: it resembles a series of old ruined castles extending for five miles from sea to sea[156].