During the war, the islands contained major Japanese airfields and defenses.   At the height of its defense, there were 19,000 men under General Takashuina based on the island.   The Marianas Islands owe much of their historical significance to a single month: June 1944. The June 1944 air battle off the coast of Saipan, known as the Great Marianas Turkey Shoot, saw the destruction of over 300 Japanese aircraft. The same month, the US Navy opened one of the greatest naval expeditions ever attempted, the invasion of Saipan, Tinian and Guam in the Mariana Islands known as Operation Forager.

  They were liberated during the summer of 1944 by the US Marines during amphibious attacks, that followed the Navy's successful action. Following their liberation, they served as bases for the B-29 "Superfortress" bombing campaign against the Japanese home islands. The bombers that delivered the first atomic weapons used in combat flew from this island group.

  The Caroline Islands extend for nearly 2000 miles across the west-central Pacific. Bordered on the east by the Marshall and Gilbert Islands, the Islands extend to within about 500 miles of the Philippines. Bordered on the south by the equator, the Islands extend to about 10 degrees north. There are probably over one thousand islands in the Carolina group. The eastern-most islands are similar to the coral islands of the Marshalls, but to the west the islands are combined with coral and lava construction. Since they lie within ten degrees of the equator and receive the southeast trade winds from the central Pacific, the islands are very hot and very humid during all months of the year.
 

  The Japanese had established several strongholds in the Carolines. These included Truk, Yap, Pelelui, Anguar, and Ulithi. The Carolina Islands were the next objective for the United States Navy. With the Gilberts, Marshalls, and the Marianas in U.S. hands, the removal of Japanese bases in the Carolinas would clear the Japs out of the central Pacific, and open the doors for attacks on the Philippines, the Ryukyu Islands, and Japan proper.