Pictures That Made Us Say "Oh, That's How They Do That!"

If you’ve spent any time lurking on Reddit’s mildlyinteresting, interestingasf*ck, or damnthatsinteresting subreddits, you’ve seen them: those pictures that make you slap your forehead and go, “So that’s how they do that!” They’re pictures that give you a behind-the-scenes peek at how common things function, are assembled, or are maintained.

Below are just some of the most interesting pictures of this kind, from Reddit and beyond. Vote up the ones that blew your mind at least a little.