America wasn't always prosperous. Eighty years ago we had plenty of people who tied their pants with a rope and pointed at airplanes in the sky.
So during the Great Depression, the U.S. Government did something smart. The Works Progress Administration, or WPA, was formed to get millions of Americans back to work, building roads, bridges, parks and public buildings.
And in a move that's difficult to imagine now, in 1935 the WPA set up Federal Project Number One, which was specifically designed to support and employ creative folk of all stripes—artists, musicians, writers and actors. Focusing on the first group, over 5,000 artists were commissioned to create posters, murals and paintings. While you've undoubtedly seen the posters created later in the program, when America had entered World War II...
...the earlier and non-war-related stuff you may not have seen. Some were public service announcements warning citizens of the dangers of the time:
This one was either done by an abstract painter or the World's Worst Police Sketch Artist:
I think this one is meant to encourage you to beware of shadowy giants coming out of the sea in the mornings:
Other posters were meant to encourage citizens to visit and support local and national attractions (though with what money, I don't know):
Another form of PSA's were meant to remind that as crappy as things were, they were once far worse. New Yorkers no longer had to buy drinking water—called "tea water" back in the day—out of barrels from some dude that smelled like horses:
The times being what they were, there was of course gender division in some of the targeting, with men being called out to pursue certain gigs...
...and women, others. In this poster she's either washing a dish, or magically turning graph paper into hubcaps.
And in advertisements supporting the other creatives included in Federal Project Number One, I found this gem...
...which undoubtedly served as an inspiration to some artist in the '60s:
In any case, if you're looking for some old-school graphic design inspiration, the Library of Congress has this amazingly deep online catalog of WPA posters. They're free to browse and download, and there are way more of them than you can get through in a sitting. Check it out and bookmark it for reference.