1. They were built about 4,500 years ago, and made to imitate the rays of the sun
2. The largest (Pharoah Kufu's) has an estimated 2,300,000 Limestone blocks
3. Each block weighs an average of 5,000 pounds and the biggest are about the size of an SUV
4. The pyramids were not built by slaves, but by Egyptian citizens. It was a profession/honor to work on the Pyramids (remember: they regarded the Pharaohs as gods).
5. I GOT TO GO INSIDE THE BIGGEST ONE! But alas, no pictures were allowed.