“Professor Michel Barsoum, Distinguished Professor in the Department of Materials Science and Engineering at Drexel University, and colleagues have found scientific evidence that
parts of the Great Pyramids of Giza were
built using an early form of concrete, debunking an age old myth that they were built using
only cut limestone blocks.”
In other words, some other material was used in some places, but most was built using limestone blocks. Article goes on: to save the planet from AGW use these methods...