If you’ve ever used the internet before today, we’re pretty sure you’ll know the drill when it comes to ‘when you see it…’ photos. But, just in case, we’ll explain it. Each one of these 13 photos has a little hidden surprise in it, which you might not notice at first. In some cases, it only takes a split second to figure out what’s really going on or what’s hidden in the background, but in other cases you might be puzzling it out for a few minutes. Take a look at these photos and see what secrets they hold!