Contrary to popular belief, it was only one of the pyramids, the Great Pyramid of Khufu, which was classified around the 5th century BC as a Wonder with a capital 'W'.

To build the Pyramid of Khufu, experts estimate that 84,000 people employed for 80 days a year worked for 20 years to complete it. Incredibly, for 40+ centuries it was the tallest man-made structure on earth, only surpassed by the 19th century's high-tech construction techniques.

The other two pyramids in the complex - Khafre and Menkaure - while still pretty impressive, are easily overwhelmed by the sheer scope of their bigger cousin. But together they form a truly majestic spectacle.

So why did a large fraction of Lower Egypt's male population sweat for most of their adult lives to create this stupendously timeless structure? It seems Pharaohs went out of their way to prove their incredible stature for the present and for coming generations, competing with each other to the point where poor Pharaoh Khafre, who built his pyramid after Khufu, had to put his smaller pyramid on top of a mound to make it look bigger, as well as covering the lower steps with granite to make them look impressive.

Whatever their size, perhaps the most amazing thing about them is that a ruler actually had the sheer autocratic will and ambition to order them made! Turning the constructive efforts of a whole empire towards building a monument to oneself, taking more than 20 years, is no mean task...