He doubled the area of the enclosure round the Temple, and there can be little doubt that a great part of the walls of the Haram area date from the time of Herod, while probably the tower of David, which still exists near the Jaffa Gate, is on the same foundation as one of the towers adjoining his palace.
A theory frequently put forward is that it stood within the Haram area near the Mosque of el Aksa, but it is more probable that it was on Zion, near the traditional place of the Coenaculum or last supper, where the Mahommedan building known as the tomb of David now stands.
Another shorter valley began near the present Jaffa gate and, taking an easterly direction, joined the Tyropoeon; while a third ravine passed across what is now the northern part of the Haram enclosure and fell into the valley of the Kidron.
North of the Temple enclosure there was a gate, known as the Sheep Gate, which must have opened into the third valley mentioned above, and stood somewhere near what is now the north side of the Haram enclosure, but considerably south of the present north wall of the latter.
At this point in the Haram enclosure there is an enormous underground cistern, known as the Great Sea, and this may possibly have been the source of water supply for the Greek garrison.