It's not like a someone woke up one day in ancient Egypt and decided to build a pyramid. Someone built a raised platform, someone else realized that if you built a raised platform on top of another raised platform, you could get a higher raised platform, eventually people started making ziggurats (Google Chrome says that's not a correctly spelled word. Hmmm) . Then someone decided that a pyramid was prettier than a ziggurat. And so on and so forth. There was no one person who designed a pyramid from scratch. They were designed over thousands over years, with huge amounts of resources being consumed. I don't think most people could build a bird nest, but that doesn't mean that humans aren't smarter than birds.