The view is reconstructed from the north, the conventional mound in the foreground covering the Central Citadel now partially excavated. The Sacred Road passes through the Ishtar Gate and along the east side of the palace; further to the east and within the fortifications is the small temple of Ninmakh. The innermost wall encloses the palace of Nebuchadnezzar with its four open courts; the façade of the Throne Room, with three entrances, is visible in the Great Court. The flat roofs of the palace are broken here and there by smaller courts or light-wells. Compare the ground-plan on p. 30, Fig. 6. (After Andrae.)] The outer city-wall, already described, dates only from the Neo-Babylonian period, when the earlier and smaller city expanded with the prosperity which followed the victories of Nabopolassar and his son. The eastern limits of that earlier city, at any rate toward the close of the Assyrian domination, did not extend beyond the inner wall, which was then the only line of defence and was directly connected with the main citadel. The course of the inner wall may still be traced for a length of seventeen hundred metres by the low ridge or embankment,[35] running approximately north and south, from a point north-east of the mound Homera.[36] It was a double fortification, consisting of two walls of crude or unburnt brick, with a space between of rather more than seven metres. The thicker of the walls, on the west, which is six and a half metres in breadth, has large towers built across it, projecting deeply on the outer side, and alternating with smaller towers placed lengthwise along it. The outer or eastern wall has smaller towers at regular intervals. Now along the north side of the main or Southern Citadel run a pair of very similar walls,[37] also of crude brick, and they are continued eastward of the citadel to a point where, in the Persian period, the Euphrates through a change of course destroyed all further trace of them.[38] We may confidently assume that in the time of Nebuchadnezzar[39] they were linked up with the inner city-wall to the north of Homeni and formed its continuation after it turned at right angles on its way towards the river-bank. This line of fortification is of considerable interest, as there is reason to believe it may represent the famous double-line of Babylon's defences, which is referred to again and again in the inscriptions. [Illustration: FIG. 6. PLAN OF THE SOUTHERN CITADEL.