TOPSHOT - Postcards featuring the World War II British slogan 'Keep Calm and Carry On' are seen outside a newsagents in London, on 24 June, 2016. 
Britain voted to break away from the European Union on June 24, toppling Prime Minister David Cameron and dealing a thunderous blow to the 60-year-old bloc that sent world markets plunging. / AFP PHOTO / LEON NEAL        (Photo credit should read LEON NEAL/AFP/Getty Images)