The IVth Dynasty has a peculiar and unique interest for the casual observer of Egyptian history, because it was the time when the world-famous pyramids were erected, the pyramids which were accounted among the wonders of the world in classical antiquity, and the name of which has stood almost as a synonym of Egypt for all succeeding generations. If one were to list the wonders of the world in our day, the legitimate number would swell far beyond the classical estimate of seven; but it may be doubted if among them all there would be any more justly accounted wonderful than these same pyramids. Even if constructed to-day, they would be accounted marvellous structures; and, dating as they do from remotest antiquity, when the devices of the modern mechanic were yet undreamed of, they seem almost miraculous. Nothing that any other land can show at all rivals or duplicates them; they are unique, like Egypt herself. What adds to the unique interest of the pyramids is the fact that we know almost nothing of their builders, except what these structures themselves relate. The pyramids epitomise the history of an epoch. They are the standing witness that Egypt in that epoch was inhabited by a highly civilised people. But practically all that we know of this people is that they were the builders of the pyramids. Even that is much, however, and we shall advantageously dwell at length upon these monuments, viewing them from as many standpoints as possible--through the eyes of Diodorus on the one hand, and of the most recent European explorers on the other.[a] [Sidenote: [_ca._ 3733-3633 B.C.]] Diodorus, voicing the traditions of his time, gives the following entertaining account of these marvels:[2]