The island chain saw significant fighting during World War II. Guam, a possession of the United States since 1898, was captured by Japan in an attack from the Northern Mariana Islands that began on the day of the Japanese attack on Pearl Harbor (December 8, 1941, the same time as the Pearl Harbor attack across the International Date Line). In 1944, the United States captured the Mariana Islands chain from Japan: the Northern Mariana Islands were desired by the U.S. as bombing bases to reach the Japanese mainland, with the invasion of Saipan being launched for that reason in June before the U.S. even moved to recapture Guam; a month later the U.S. recaptured Guam and captured Tinian. Once captured, Saipan and Tinian's islands were used extensively by the United States military as they finally put mainland Japan within a round-trip range of American B-29 bombers. In response, Japanese forces attacked the bases on Saipan and Tinian from November 1944 to January 1945. At the same time and afterwards, the United States Army Air Forces based on these islands conducted an intense strategic bombing campaign against the Japanese cities of military and industrial importance, including Tokyo, Nagoya, Osaka, Kobe, and others. Both the "Enola Gay" and the "Bockscar" (which dropped atomic bombs on Hiroshima and Nagasaki, respectively) flew their missions from Tinian's North Field.