Currently, the sides of the pyramids consist of a series of stone blocks weighing between 2 and 15 tons. The stone blocks form giant steps up the side of the pyramids. However, originally, large triangular polished limestone casing stones were placed on each of these steps so that the facade of the pyramids was a giant smooth surface. It is know that these casing stones existed because some of them can still be found on the pyramids and in the rubble littering the desert adjacent to the pyramids.