In reflecting upon such a history as this, two things become very clear; the first is that the details of the events would be much better understood if we had an accurate map before us; the second is that the events themselves--the successive destructions and rebuildings--must have changed the city considerably from what it was. Even in the city of London the floors of Roman dwellings are found 15 or 18 feet below the present surface of the streets. In Jerusalem, we need not be surprised to learn, the depth of _debris_ is much greater, and since it has accumulated chiefly in the valleys, and very nearly obliterated some of them, it has, of course, obscured the topography. An accurate map of modern Jerusalem is in our hands, but it does not show us what the ancient city was like. Therefore it is not sufficient to have this modern map before us when we read the ancient history. We read in the history that Zedekiah fled (from his palace) through the gate between two walls and by the way of the king’s gardens; but in modern Jerusalem there is no king’s palace or garden and no gate between two walls. The history describes how Nehemiah rebuilt the wall, from the Sheep Gate to the Tower of Meah, and thence to the Fish Gate, and the Old Gate, &c., but in modern Jerusalem we find no such places and names. We are still worse off when we read in Josephus about Titus encamping within the third wall, and then making a breach in the middle wall and encamping in the middle city, and still having a wall between him and the Jews in the Upper City: for the Jerusalem of to-day shows only one wall besides the rampart of the temple. Naturally there has been much conjecture concerning the ancient city, and the best authorities have differed from one another in their ideas. It was with the hope of settling the disputed questions as well as with the object of uncovering antiquities, that the Palestine Exploration Society began the work of excavation.