The post office
So far, none of the locations on this list should have been too surprising. But the post office? Really? Yes, there are actually guidelines for taking photos inside a U.S. post office. You can only take photos for personal use at the discretion of the postmaster, as long as they don't disrupt the employees and are taken in areas that are accessible to the public. But wait, there's another big caveat: "No picture can depict any Postal Service employee, customer, security camera, or cover of mail (i.e., the exterior of a mailpiece, which would show customer name and address among other things)." Once all of those things are taken out of the equation, there's not a whole lot you'd want to take a photo of anyway. Here are more strange things you won't believe are banned in the United States.
10 Places That Forbid You from Taking Pictures, Source:https://www.rd.com/list/places-forbid-taking-pictures/