- After Jiaozhou Bay was ceded to the Germans in May 1897, the small fishing village of Qingdao turned into the military hub of the German Navy. The city became the naval nerve center of all German operations in the Pacific ocean. It was the Germans, homesick and in great need of beer, who constructed and opened the hallmark Tsingtao Brewery in 1903.
- In the antebellum period of World War I, the Germans were forced to Flee after the British and Japanese combined forces and laid siege to the outpost. The Japanese maintained control over the city (and the brewery) until 1922, when it was returned to China. But in 1937, the Japanese reoccupied the city as part of their expansion into mainland China.
- After World War II, the city served as a U.S. naval port for a brief period before the founding of the PRC.
