One may have to search out the original sources to verify the following Wikipedia entry at [en.wikipedia.org]
"At the end of the twelfth century al-Malek al-Aziz Othman ben Yusuf, Saladin's son and heir, attempted to demolish the pyramids, starting with Menkaure's.
The workmen whom Al-Aziz had recruited to demolish the pyramid found it almost as expensive to destroy as to build. They stayed at their job for eight months. They were not able to remove more than one or two stones each day at a cost of tiring themselves out utterly.
Some used wedges and levers to move the stones, while others used ropes to pull them down. When a stone fell, it would bury itself in the sand, requiring extraordinary efforts to free it. Wedges were used to split the stones into several pieces, and a cart was used to carry it to the foot of the escarpment, where it was left.
Far from accomplishing what they intended to do, they merely spoiled the pyramid by leaving a large vertical gash in its north face."