Immediately beneath the foundation stone is a natural cavern in the rock, (a natural underground cistern), from which it is believed that the original Gihon spring may have flowed before being redirected in the days of Hezekiah, (2 Chronicles 32:30), but of course that is debatable. However the hollow cavern in the rock underneath was found in the times of the Crusaders and they opened up a side tunnel into it, (thinking they were going to find treasure). The hollow cavern underneath the Foundation Stone is now called the "Well of Souls" by the Arabs. The hole in the top of the Rock, which appears in the image file above like as if the eye of the Lion, actually goes through into the Well of Souls. The Arabs still hang a lamp down through it to light the inside of the Well of Souls. Are you getting the imagery? It is profound, for Yeshua says, even well before all of these things occurred, "The lamp of the body is the eye: if therefore thine eye be single, thy whole body shall be full of light", and here we have a single eye in the face of the Lion of Yhudah, and a lamp in its single eye to light the inside which is called the Well of Souls.
http://science.nationalgeographic.com/science/archaeology/well-of-souls/
http://1.bp.blogspot.com/-8VMeN2gzGhg/Tk1W_Mu5LeI/AAAAAAAAAwE/kAbqV8677Hg/s320/well-of-souls.jpg