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It's as vexing as the riddle of the Sphinx. And the truth is, no one really knows how they built the pyramids.

But amateur Egyptologist Maureen Clemmons has a theory. She thinks that kites may have been used to build the pyramids.

"If you look at the top center of every monument, you see wings," Clemmons said. "I think the Egyptians have been trying to tell us in pictures for 3000 years that this is how they built the pyramids."

Her idea - to build a pyramid you harness the desert wind using kites to lift the stones. She got a team of aeronautic engineers from Caltech to help her test the theory.

"At the beginning, we were ourselves very critical of her ideas but then we started to think more about it and we said, 'why not? let's try it,'" said Mary Gharid of Caltech.

The engineers worked out the math and designed a system of nylon ropes and pulleys. Each pulley quadruples the amount of weight a single kite can pull.

"So, we're using one kite in 15 mile per hour winds to lift up a three and half ton block," said Caltech student Emilio Castano.

Yesterday, in the Mojave Desert, they put their theory to the test using a nylon kite, three pulleys and an obelisk that weighs nearly four tons.

The wind speed had to be just right. And miraculously, it worked. There was more than enough force to hoist the obelisk. The total airtime? Only twenty-five seconds.

But the fact that it can be done, doesn't necessarily mean that's how the ancient Egyptians did it.

"There's absolutely no evidence for kites in ancient Egypt," said Professor Carol Redmount of UC Berkeley. "There's no evidence of pulleys as we know them today."

Redmount says the historical evidence points to the "Charlton Hesont method." Which basically relies on the theory of the muscle of slaves pushing pulleys and creating the pyramids.

But the Caltech group will have none of that.

"All I can remember from history is that Egyptians drank beer for breakfast, lunch and dinner, and as someone who has done field research on drinking beer, I know after I've had two beers and its really hot, I'm not pushing or pulling anything," Clemmons said. "So, I figured I'd try to think another way."

(Agencies)