What's always stunned me is that the pyramids were already close to 3,000 years old when Jesus was born.
I remember reading a dispute that they may be significantly older than that, even. <Goes to find a
link> Because Khufu is only mentioned in one place and isn't mentioned all over the pyramid (like most other burial chambers), they think he was added much later. Some think they were built as far back as 10,500 B.C., because of an alignment with Orion that would only have occurred at that time (and the Spinx, coincidentally, would align with Leo that same time.) There, I saved you from clicking the link.
It's a rather interesting theory.