By Dan Vergano, USA TODAY
The Great Pyramid of Giza, the sole surviving member of the Seven Wonders of the Ancient World, stands today as the most massive puzzle in the history of civilization.
From the ancient Greeks to today's techno-geeks, many have asked this question: How was something this huge built with such precision? The entire 13-acre pile of limestone blocks, most weighing more than 2 tons, has sides no more than 8 inches out of alignment, says archaeologist John Romer, author of The Great Pyramid: Ancient Egypt Revisited, released in April. Its interior shafts, some hundreds of feet long, vary less than a few inches from being perfectly straight.
Now French architect Jean-Pierre Houdin has reopened this conversation with a controversial proposal that the giant tomb of the pharaoh Khufu (Cheops to the Greeks), who reigned from about 2589 B.C. to 2566 B.C., was built from the inside out with the use of internal ramps.
The theory challenges decades of archaeological thought about how the pyramid was built, and graces the cover of the current Archaeology magazine, published by the Archaeological Institute of America. But Egypt's chief archaeologist isn't impressed. "I receive a theory every day," says Zahi Hawass, secretary general of the Supreme Council of Antiquities.
The ancient Greek historian Herodotus reckoned around 2,500 years ago that 100,000 slaves worked for 20 years to achieve this near-perfection. More than 2 million stone blocks, 5.5 million tons of stone, are placed atop one another inside the pyramid, Romer says.
The Great Pyramid has long hinted at some sort of numerological secret in its construction. Its four sides, if added together by length, would equal the diameter of a circle with a radius equal to the original 481-foot height of the structure.
In Cairo last week, Hawass heard Houdin's presentation of his belief that the pyramid builders constructed a series of ascending internal ramps to lift the blocks from the ground and into place. The ramps remain inside the pyramid, detectable by sensors, Houdin says.
In May's Archaeology, Long Island University archaeologist Bob Brier outlines the conventional ideas of how workers built the pyramid:
• A massive ramp outside the pyramid led straight from a limestone quarry to the pyramid.
• Simple wooden cranes hoisted the blocks up step-by-step, removing a need for a ramp.
• A spiral ramp was built outside the pyramid.
All have problems, Brier says: Too much labor and stone would be needed for the outside ramp; there's not enough available wood for cranes; and a spiral ramp would ruin external sightlines.
Working with Mehdi Tayoubi of the French software firm Dassault Systèmes, Houdin created a model of the internal ramps built in steps atop the rising pyramid walls. The ancients needed clear external sightlines to check how precisely the blocks of the pyramid were layered, because they had only rope lines as measuring devices. So, he argues, the two-lane internal ramps preserved the structure's outer face for such measurements.
Microgravimetry, which can detect hollows beneath closed spaces, along with ground-penetrating radar could reveal the hidden internal ramps, Houdin says. But Hawass says he's not in favor of such testing, for now. "The pyramids built directly after Khufu's do not have any evidence of an internal ramp," Hawass says by e-mail.
And Romer dismisses Houdin's idea. "In reality, huge amounts of well-documented facts exist concerning the genuine building methods employed," he says. "Quite simply, we see the outline where a ramp ends in a quarry."
"Every age reinvents the pyramid's purposes and meaning," Romer adds. "We end up ignoring the real achievement of these people."
"The process will be surely long, and no one is in a hurry," Tayoubi says by e-mail. "We understand that some other preliminary tests on other sites are necessary." After all, Houdin says, the pyramid has retained its mystery for 4,500 years. A few more won't hurt.
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