A flat platform was built around the peak of the Temple Mount, carrying the Dome of the Rock; the peak just breaches the floor level of the upper platform within the Dome of the Rock, in the shape of a large limestone outcrop, which is part of the bedrock. Beneath the surface of this rock there is a cave known as the Well of Souls, originally accessible only by a narrow hole in the rock itself; the Crusaders hacked open an entrance to the cave from the south, by which it can now be entered.