Exactly 70 year ago to the day, the military forces of Nazi Germany invaded the neutral countries of Holland and Belgium (as well as Luxembourg). In these countries, May 10, 1940 is marked as the beginning of World War Two.
For the French and British, it also marked the transition to “hot” warfare from the phase of “drôle-de-guerre”/”Phoney War” that followed the declaration of hostilities on September 3, 1939.
Holland fell after just four days of resistance, while Belgium hung on for a total of 18 days. The supposedly impregnable French fixed border fortifications (the Maginot Line) did not extend along the French border with Belgium, and after reducing the Eben-Emael fortress in Belgium the Wehrmacht was easily able to flank the Maginot line and invade France.
Four (for Holland: five) long years of occupation awaited, until the Western Allies were able to effect liberation.