A gray fog hovered over the masses assembled on the beaches around Dunkirk. Usually the English Channel tossed and rolled, but today the waves were calm. Looking out to sea, the tired soldiers knew their only hope of survival lay in reaching England. Could they make it? Would they be destroyed by the German army, getting closer each hour?

During the years before the Second World War, few people took Hitler and his crazy ideas seriously. When Winston Churchill tried to warn the world about Hitler, no one listened. Austria and Czechoslovakia were captured by Germany without fighting—but when the Nazis invaded Poland in 1939, it finally became apparent that Hitler must be stopped. The Allied forces of England and France agreed to help if Belgium suffered invasion.

In 1940, the Germans did indeed attack Belgium.

The Germans employed a new kind of warfare called Blitzkrieg—lightning war. Expecting the Germans to march through Belgium just as they had in World War I, the Allies sent most of their troops there. Instead, the Nazis marched through the Ardennes, which everyone thought impassable for tanks. The Germans advanced swiftly, and soon they pushed the Allied troops toward the sea. Since the assault took the Allies by surprise, many troops didn't know where they were or what they should be doing. One thing was crystal clear: they were being defeated. The attack on Belgium began on May 10, and by May 24 the Germans had pushed so far into France that Hitler feared his tanks would be separated. On May 24 he gave a halt order. This gave the tanks a chance to regroup, but it also gave the Allies a needed reprieve and helped save many men from certain death.

For over two weeks the Allied soldiers had been marching or fighting every day. Their fatigue overwhelmed them. A few clever men devised a way to sleep while marching! Three men abreast would lock arms, and the two on the outside kept the middle man in step. That way he would be able to sleep while he marched. Each took a turn in the middle.

When the troops began heading north, they were told to congregate at Dunkirk. A large, billowing cloud of black smoke served as a beacon to the troops. An oil refinery and oil tanks at Dunkirk had been bombed by the Germans, and the smoldering clouds emitted were a blessing in disguise. They led the shattered troops to Dunkirk. The clouds also hid many of troops' activities from the Luftwaffe, the German air force. Even though the German tanks were temporarily stationary, the Allies still suffered from air attacks. Hitler wanted the glory of victory to go to the Luftwaffe. Goering, the commander of the air force, even bragged, "My Führer, leave the destruction of the enemy surrounded at Dunkirk to me and my Luftwaffe!" However, the Luftwaffe's attacks were indecisive, and on May 27 the tanks began moving again. By now large numbers of troops had reached Dunkirk, including many of the British Expeditionary Force (BEF).

Initially, evacuation seemed unnecessary. The troops needed to regroup, dig in, and fight again. At least, that's what the military leaders in England thought—but the field commanders knew the time had come to retreat. The Germans marched across France and surrounded the Allies. Pushing them in a semicircle closer and closer to the sea, the Germans squeezed a little tighter each day. As early as May 22, 1940, plans were put into action to evacuate the troops. The Admiralty met in the "Dynamo Room," which served as part of their offices under Dover Castle. Thus the evacuation bore the codename "Operation Dynamo."

On May 26, the first troops were transported from Dunkirk to England, and the evacuation continued until June 4.

Since the retreat of the BEF and their Allies was chaotic, it's no wonder the evacuation lacked organization too. Adding to the disorder were the attacks from the Luftwaffe. On May 27 and 29 and June 1, the Luftwaffe led devastating attacks on the ships and men at Dunkirk. Other days, the Luftwaffe were still a threat, but not as effective. Not only was there danger from the air: the calm water also hid mines and German submarines. When the evacuation started, Britain had 40 destroyers, but by the end only 11 remained. For the soldiers, getting on a ship was not a sure ticket home; many soldiers died or found themselves stranded in the water when their transports sank. Frequently, survivors were picked up by other ships.