We all know the Circus of Values clown. We've all bought ammo, EVE hypos and health kits "from him" dozens of times. But did you know that he originally sold melons?
While the fact that some of the BioShock series' period artwork appears to have been inspired by real-world vintage advertisements was already known (shown on the BioShock wiki, for example, here, here and here), this extensive GIF album, put together by redditor UpgradeTech, does a really good job of showing off these influences. In fact, UpgradeTech was the one responsible for uploading many of the original ads on the Wiki in the first place.
Here's the album. Be warned, GIF #5 is NSFW.