The Bent Pyramid, Dahshur — the most honest monument in Egypt. Built for Pharaoh Sneferu around 2600 BC, its sides begin at 54 degrees then abruptly shift to 43 degrees halfway up as the engineers recognized a structural problem and corrected it mid-construction. It also retains nearly all of its original smooth limestone casing — the closest thing to seeing what Giza once looked like.
© Lexie, CC BY 2.0, via Wikimedia Commons