In the Battle of the Aleutian Islands during World War II, U.S. Troops fought to remove Japanese garrisons established on a pair of U.S.-owned islands west of Alaska.
In June 1942, Japan had seized the remote, sparsely inhabited islands of Attu and Kiska, in the Aleutian Islands.
It was the only U.S. Soil Japan would claim during the war in the Pacific. The maneuver was possibly designed to divert U.S. Forces during Japan's attack on Midway Island in the central Pacific.
It’s also possible the Japanese believed holding the two islands could prevent the U.S. From invading Japan via the Aleutians.
Either way, the Japanese occupation was a blow to American morale. In May 1943, U.S. Troops retook Attu and three months later reclaimed Kiska, and in the process gained experience that helped them prepare for the long "island-hopping" battles to come as World War II raged across the Pacific Ocean.
More people were killed during this battle than at Pearl Harbor.