Despite being neutral at the start of World War I, Belgium its colonial possessions found themselves at war after the country was invaded by German forces, Operation Yellow, on 10 May 1940. After 18 days of fighting in which Belgian forces were pushed back into a small pocket in the north-east of the country, the Belgian military surrendered to the Germans, beginning an occupation that would endure until 1944. The surrender of the modest Belgium army of 28 May was ordered by King Leopold III without the consultation of his government and sparked a political crisis after the war. Despite the capitulation, many Belgians managed to escape to the United Kingdom where they formed a government and army in exile on the Allied side.
The Belgian Congo remained loyal to the Belgian government in London and contributed significant material and human resources to the Allied cause. Many Belgians were involved in both armed and passive resistance to German forces, although some chose to collaborate with the German forces. Support from far right political factions and sections of the Belgian population allowed the German army to recruit two divisions of the Waffen SS from Belgium and also facilitated the Nazi persecution of Belgium Jews in which nearly 25,000 were killed, In Holland 106.000 Jews were killed.
Most of the country was liberated by the Allies between September and October 1944, though areas to the far east of the country remained occupied until early 1945. In total, approximately 88,000 Belgians died during the conflict a figure representing 1.05 percent of the country’s pre-war population, and around 8 percent of the country’s GDP was destroyed. In Holland 200.000 people didn’t survive the war.