I suppose they have figured out the mystery of the Pyramids. 

From the article:

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.

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. According to his theory - shown in a computer model available at http://www.3ds.com/khufu - the builders put up an outer ramp for the first 140 feet, then constructed an inner ramp in a corkscrew shape to complete the 450-foot structure.

Houdin also postulated that King's Chamber was hoisted into place through a system of counterweights.

What do you think?