It's a print that has launched a thousand parodies (and twice that many Etsy products) but a recently posted YouTube video explains the history behind those ubiquitous "Keep Calm & Carry On" posters. The British government designed three propaganda posters in 1939, each featuring a "smart and handsome" typeface and the crown of King George.

Although 2.5 million copies were printed, this poster was never officially distributed. It was entirely forgotten until a copy was discovered in a used bookstore in northern England. That shop, Barter Books, is responsible for this three-minute reminder that Keep Calm's "simple heartwarming message" is as appropriate now as it was then.