How to Build a Pyramid
Of the seven wonders of the ancient world, only the Great Pyramid of Giza remains. An estimated 2 million stone blocks weighing an average of 2.5 tons went into its construction. When completed, the 481-foot-tall pyramid was the world's tallest structure, a record it held for more than 3,800 years, when England's Lincoln Cathedral surpassed it by a mere 44 feet.
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Link : Hidden ramps may solve the mystery of the Great Pyramid's construction.