The poster "Keep Calm and carry on" that was created by the British Government during the WWII to boost the morale of the British people in case of a Nazi's invasion. The poster was never used and was destroyed. In 1945 a bookseller found a few of them and there are copies at the National Archive. It was at the beginning of this century that it was bring to the public by private companies and is being used to decorate mugs, t-Shirts and whatever the industry sells. You can read more here. There are many funny recreations, parodies and subversions of the poster and these are some of them to be added to the one I have already posted. You can create or own version if you go here. I did my version and I will publish it next week.