Originally a propaganda piece designed to keep war-fearing British citizens from stopping everything and freaking the fuck out, the WWII-era "Keep Calm and Carry On" design has since become an iconic design sold on everything from wall hangings to coffee mugs. Your girlfriend has it on a totebag.
According to the UK's Barter Books, they're the ones who originally dug up the design relic and started selling it on things again, and to make that case, they've put together this brief, stylish, informative short about the poster's origins and revival. Try to ignore how desperately the narrator needs some wah-wah. It's only three minutes.
I hope a U.S. anti-terrorism sign one day resonates so loudly, an eternal message of NO SNOW GLOBES.