Attention is called to the granite plugs filling the ascending passageway to the Queen's Chamber which Caliph al Mamoun was forced practically to pulverize before he could clear a way into the upper chambers. C. Piazzi Smyth notes that the positions of the stones demonstrate that they were set in place from above--which made it necessary for a considerable number of workmen to depart from the upper chambers. How did they do it? Smyth believes they descended through the well (see diagram), dropping the ramp stone into place behind them. He further contends that robbers probably used the well as a means of getting into the upper chambers. The ramp stone having been set in a bed of plaster, the robbers were forced to break through it, leaving a jagged opening. Mr. Dupré, an architect who has spent years investigating the pyramids, differs from Smyth, however, in that he believes the well itself to be a robbers' hole, being the first successful attempt made to enter the upper chambers from the subterranean chamber, then the only open section of the Pyramid.