During World War II, small parts of the Aleutian islands were occupied by Japanese forces, when Attu and Kiska were invaded in order to divert American forces away from the main Japanese attack at Midway Atoll. The U.S. Navy, having broken the Japanese naval codes, knew that this was just a diversion, and it did not expend large amounts of effort in defending the islands. A few Americans were taken to Japan as prisoners of war. Most of the civilian population of the Aleutians were interned by the United States in camps in the Alaska Panhandle. During the Aleutian Islands Campaign, American and Canadian forces invaded Japanese-held Attu and defeated the Japanese, and subsequently regained control of all the islands. The islands were also a stopping point for hundreds of aircraft sent from California to Russia as part of the war effort.[dubious – discuss]Monday, June 3, 2002 was celebrated as Dutch Harbor Remembrance Day. The governor of Alaska ordered state flags lowered to half-staff to honor the 78 soldiers who died during the two-day Japanese air attack in 1942. The Aleutian World War II National Historic Area Visitors Center opened in June 2002.