Did the Egyptians Invent Concrete?

The Egyptians may have used concrete to build the pyramids, an MIT professor suggests, and he's using materials available at the time (and students as his slave labor), to test the theory on a small mock-up of a pyramid, reports the Boston Globe. "It could be they used less sweat and more smarts," says Linn Hobbs, a materials science prof, by casting in place blocks on the upper reaches of the pyramids using wooden molds.

If so, it would have saved millions of man-hours, the Globe notes, and pushed back the invention of concrete 2,000 years before the Romans used it in their structures. Egyptologists and archaeologists are almost universally opposed to Hobbs' theory, pointing out that there is simply no evidence to support it. (More Pyramids stories.)