(2) _Underground Tunnels._--In time of war, when a city might be shut up for years, cities were often compelled to yield for want of water. This was especially the case if the spring lay outside the city walls. In several Palestinian cities means were taken to secure access to a spring without exposing oneself to the enemy outside the wall. One of the greatest of these undertakings was discovered at Gezer. This was a tunnel cut in the solid rock, which was entered by a long flight of rock-cut steps. At the entrance the rock formed an imposing archway 23 feet high and 13 feet 10 inches broad. These dimensions were maintained throughout about two-thirds of the length of the tunnel. The whole passage was about 130 feet long. The last third of it had to be cut through a much harder rock, where the work was much more difficult, and its workmanship was here not so good as above. The tunnel also became appreciably smaller. The passage terminated in a large cave, in the bottom of which was a spring, and was evidently constructed to enable the inhabitants to reach a water supply in time of siege. The floor of the cave is 94 feet 6 inches below the level of the rock surface under the ancient city. The whole tunnel is a remarkable piece of engineering for an early people; (see Figs. 60 and 62). The earth with which the mouth of the tunnel was closed contained objects which belonged to the time 1450-1250 B. C. The steps in the passageway had been before this deeply worn by many feet--so deeply worn that Mr. Macalister estimated that they must have been in use for 500 years. For these reasons he supposes that this water-passage was excavated about 2000 B. C. or soon after that date. It had ceased to be used before the Israelites conquered the place. A similar underground tunnel leading to a spring has been found at El-Gib, Gibeon, (Fig. 63), and one made in Jebusite times also existed at Jerusalem. It is mentioned in 2 Sam. 5:8, and will be described in connection with Jerusalem (p. 188). At Rabbah Ammon an underground passage connected the old city situated on the hill with a large cistern which was roofed over so as to be concealed. To this cistern in time of siege the inhabitants could go through the passage and obtain water. It was this cistern[153] which Joab had captured (2 Sam. 12:27) when he sent to David to come and take the city. Antiochus III of Syria in the same way compelled the city to surrender in the year 218 B. C.,[154] and Herod the Great did the same thing before 30 B. C.[155]