The direct involvement of the Netherlands in World War II began with its invasion by Nazi Germany on 10 May 1940. The Netherlands had proclaimed neutrality when war broke out in September 1939, just as it had in World War I, but Adolf Hitler ordered it to be invaded anyway. On 15 May 1940, one day after the bombing of Rotterdam, the Dutch forces surrendered. The Dutch government and the royal family escaped and went into exile in London.
Following the defeat, the Netherlands was placed under German occupation, which endured in some areas until the German surrender in May 1945. Active resistance was carried out by a small minority, which grew in the course of the occupation. The occupiers deported the majority of the country's Jews to Nazi concentration camps, with the cooperation of much of the Dutch police and civil service.
In fact, the Netherlands saw one of the highest levels of collaboration during the Holocaust of any occupied country. However, the city of Amsterdam organized the only industrial action in protest to the persecution of their Jewish fellow citizens ever in all of the Nazi occupied areas. Nonetheless, and also due to the well organized population registers comparing to other countries, about 75% of the country's Jewish population were killed during the conflict; a much higher percentage than comparable countries, like Belgium and France.
Most of the south of the country was liberated in the second half of 1944. The rest, especially the west and north of the country still under occupation, suffered from a famine at the end of 1944, known as the "Hunger Winter". On 5 May 1945, the whole country was finally liberated by the total surrender of all German forces.