In a This Day in History video, learn that on July 30, 1945, a Japanese submarine struck down the U.S.S. Indianapolis. The ship had just left a military base in the Pacific where uranium and components for the atomic bomb were delivered. The cruiser was traveling alone when two torpedoes struck; 900 men were forced into the water. Unfortunately, at sunrise, sharks began to attack those men in the water, and for three days survivors floated fending off predators. On the 4th day after the attack, survivors were spotted by an American bomber pilot who began a rescue mission; but only 316 men survived.