Theories of strategic bombing in the 1930s suggested that it alone might be enough to win a war. But the development of radar meant that the bomber might not always get through after all.
We examine the advances in aviation technology between the World Wars.
After the Dunkirk evacuation, the next stage of the Western offensive began, aimed at capturing Paris and defeating France.
After German armor cut off the Allied First Army Group in Belgium, the Royal Navy attempts an evacuation of the trapped forces from the port of Dunkirk.
After months of delays and a diversion into Denmark and Norway, Hitler finally gets his Western offensive.
The Allied debacle in Norway sparked a revolt in the British Parliament against the Chamberlain government's conduct of the war.
Improbably, the nation of Norway finds itself the front line of the Second World War.
In the final year before the war began, Winston Churchill's denunciations of Nazi Germany began to seem prescient, but Prime Minister Neville Chamberlain fiercely resisted calls to invite Churchill into the Cabinet until war came. Then Churchill became First Lord of the Admiralty, for the second time in his career.