Built 4,000 years ago, the three great pyramids at Giza, in the Egyptian desert remain the most colossal buildings over constructed.

The pyramids were built by Egyptians under the orders of the Egyptian leader, whose title was Pharaoh. There was a sequence of Pharaohs culminating around 2615 B.C., with the Pharaoh Cheops who built the biggest thing ever built, the Great Pyramid, also known as Khu fu. Cheops built a pyramid 770 feet on one side and 481 feet tall. How ancient builders managed to build these massive structures has never been fully answered but the effort clearly required brains and brown.

Was there engineering genius involved? Yes, there was. For example, when you' re pulling the block right at the top, how are you going to lug a block of stone that weighs several tons 480 feet up a structure? How are you going to do it, and how are you going to do it without leaving scratches on all the rest of the structure? And how many people does it take to drag a block weighing several tons 480 feet up into the sky? Approximately, 2.3 million blocks of stone were cut, transported and assembled to create the Great Pyramid.

The Pharaohs may have set out to build magnificent tombs for themselves, but in the end they created monuments to human potential. There's a universal message in the pyramids. The pyramids belong to Egypt, but the pyramids also belong to the world. That' s why we can all identify the pyramids as an early monument of human greatness.

For being a man-made wonder that has survived the sands of time, the pyramids rise to the number two spot.