Learning The problem with public domain is that you get to see how dumb so much public work is. For example, check out National Security Agency (NSA) security/motivational posters from the 1950s and 1960s. It’s a giant pdf of 135 posters that the NSA produced to educate and inspire Americans about their role in keeping national secrets secret. I’m imagining that these adverts were hung in the post office, right next to the Wanted posters. I'm thinking that the Wanted posters got a whole lot more attention. But hey, now they're free. While you're there, check out the entire catalog of public domain property that this website gathers and shares. Pack a lunch. It could take some time. Website: governmentattic.org