I first saw this saying framed in a little shop on Martha's Vineyard called Portobello Road.
|Portobello Road - found objects-curiosities-etctera|
|glimpse of Portobello Road Shop - Edgartown, Martha's Vineyard|
and then I found:
Anyway, I knew that the "Keep Calm and Carry On" poster originated in England but it didn't know the exact history. Then today, The Huffington Post posted this on Facebook. I thought it was interesting.