For centuries, Egypt's pyramids have been a point worldwide fascination. Scholars have long asked, how did the egyptians build them at all, much less so beautifully? But, when structural engineer Peter James looked at the pyramids, he asked why they were falling apart. The longstanding explanation is that looters have picked apart the pyramids over the years. But James wasn't convinced by that idea, which led him to a new theory that he wrote about in Structure. The engineer believes that the pyramids were constructed so precisely that they weren't built to deal with the contraction and expansion of the limestone in the desert heat, and that ironically, the most crudely built one — the Bent Pyramid — has thus held up best over the eons.