On 29 February 1944 during World War II, the Admiralty Islands were invaded in Operation Brewer led by American General Douglas MacArthur. The Americans quickly built a big base at Seeadler Harbor, including harbour, wharves and an airbase, which became an important base for the further war operations in New Guinea as well as on the Philippines. The base is today used by the PNG Defence Force. It was made famous by the work there and writing of it by the New York anthropologist Margaret Mead from the 1950s through '70s.