Adolf Hitler's megalomania knew no limits: from the very outbreak of war, his strategists were forging plans to attack the USA. The most daring of these involved suicide missions, in which squadrons of German fighter planes would crash into Manhattan's skyscrapers as living bombs. Large cargo planes would carry small planes over the Atlantic. The fighter planes would then disengage, and their pilots would steer them into the skyscrapers of New York - a 9/11 scenario contemplated half a century earlier.

Hitler had dreams of attacking the US. The dream was big, the logistics a nightmare but Hitler's determination was unbounded. So when the plans for a bomber became hobbled with problems, he brought in a host of extraordinary Plan Bs, including the use of seaplane bomber, a mid-air refuelling mission and the invasion of Iceland so the Germans could use it as an air base. On the ground, Hitler also had spies in New York sussing out potential targets. Many Nazi agents were already ensconced in the community and some literally walked in from the sea. Bizarre as it sounds, they would be taken as close to shore as possible by submarine, swim to the beach, change clothes, then catch the next train into Manhattan.