Just how WERE the Pyramids of Giza built?

Working in a biomechanics lab really gets me wondering how things are built. Lately, I’ve been wondering just what do we know about how the Egyptian pyramids were built 4,500 years ago. My pondering has brought me to some pretty interesting stuff.

First, of all, I had no idea exactly how huge the Egyptian pyramids are. Each pyramid used something like 2 million stones that were up to 15 tons each! The biggest (and oldest) of the three pyramids, The Great Pyramid, is 481 ft (147 m) tall, about the same size as the Space Needle in Seattle. Compared to modern skyscrapers, that’s not much, but consider trying to build anything on that scale without cranes, impact drills, hydraulic lifts, or, frankly, any complex machinery.  The feat becomes much more impressive, doesn’t it? So how’d they do it?