In a recent visit to Cairo my wife and I visited the Great Pyramids in the suburb of Giza. These " Wonders of the Ancient World" are AWESOME! You have to come and climb on the limestone blocks to appreciate the enormous amount of human toil that went into their construction of these giant structures. 2.3 million limestone blocks were piled upon each other to a height of 481 feet....and it was all completed 4,550 years ago with only crude instruments and human sweat!