The Deep Web and Darknet
What lies beyond the surface of the World Wide Web?
OK, type something pretty basic into Google. Pablo Picasso. Right away you'll get services trying to sell you really crappy college papers about Pablo Picasso. You'll get Wikipedia, of course. If you sharpen your search terms, you'll find other stuff, some of it even interesting. You might even find out he's the most stolen artist in the world with more than 1,000 pieces still missing.