Operation Weserübung's effects on Sweden
On 9 April 1940, Germany successfully launched Operation Weserübung, a military operation with the objective of simultaneously occupying Denmark and Norway and staging a coup d'état in those nations. The operation had several far-reaching consequences for Sweden, which became effectively cut off from trade with the Western world and so was more dependent on German goodwill.
Source: Wikipedia — Operation Weserübung's effects on Sweden (CC BY-SA 4.0)