It was a lie that made history: on 15 June 1961, Walter Ulbricht, head of state of the German Democratic Republic (GDR), denied rumours that there were plans to close the border between East and West Berlin. In fact nobody had asked if there were plans to build a wall; it was Ulbricht himself who introduced the idea into the discussion. To this day it is unclear why he did so. What is known is why he wanted to close the border. In the preceding years, millions of people had fled to West Germany from the economically depressed East. Less than two months later, construction began on probably the most famous symbol of the Iron Curtain.