Underground Jerusalem

What does underground Jerusalem look like? Apparently something like this - a jumble of walls, stones, ancient and modern garbage, underground passages and cavities - an archaeologist's dream. But... you can't dig! Because there are strong religious feelings! Just do something wrong and a criminal article, international tension, street riots, intifada and all that could be fall on your head. An archaeologist in the Middle East is like a soldier on the front line of war sometimes...