A French architect claimed Friday to have uncovered the mystery about how Egypt's Great Pyramid of Khufu was built - with use of a spiral ramp to hoist huge stone blocks into place.

AP Photo/Dassault Systemes
In this 3D computer image released by French company Dassault Systemes on Friday, March 30, 2007, the theory of French architect Jean-Pierre Houdin of an internal ramp built for the construction of the Great Pyramid is seen. During a 3D screening followed by a press conference at the Paris Geode cinema on Friday, Houdin exposed his revolutionary theory of the construction of the Great Pyramid of Khufu, arguing it was built from the inside. Houdin presented the hypothesis of an internal ramp and the use of a counterweight system. Houdin used 3D technology to have his theory confirmed.


The construction of the Great Pyramid 4,500 years ago by Khufu, a ruler also known as Cheops, has long befuddled scientists as to how its 3 million stone blocks weighing 2.5 tons each were lifted into place.

Ending eight years of study on the subject, architect Jean-Pierre Houdin released his findings and a computerized 3-D mockup showing how workers would have erected the pyramid at Giza outside Cairo.

The most widespread theory had been that an outer ramp had been used by the Egyptians, who left few traces to help archeologists and other scientists decode the secret to the construction.

Houdin said he had taken into account the copper and stone tools available at the time, the granite and limestone blocks, the location of the pyramid and the strength and knowledge of the workers.

According to his theory - shown in a computer model available at www.3ds.com/khufu - the builders put up an outer ramp for the first 141 feet, then constructed an inner ramp in a corkscrew shape to complete the 446-feet structure.

Houdin said he based his theory partially on work by fellow Frenchman Gilles Dormion, who has studied pyramid construction for more than 20 years.

Houdin also postulated that King's Chamber, situated 43 meters above the pyramid's base and capped with granite ceilings, was hoisted into place through a system of counterweights.

Houdin said he plans to verify his theories through non-invasive tests on site.