The long and costly struggle for these strategic islands was due in large measure to the numerous caves which the Japanese had blasted in the volcanic rock. These formidable fortifications frequently concealed heavy gun batteries as well as vast supplies of food and ammunition. Those that were not blasted by our heavy ships' batteries required slow and costly elimination by our ground forces. Here a couple of GI's are mopping up a cave. In the eerie light of the interior of the cave they cautiously search for signs of the enemy.