The USS Indianapolis was a Portland-class heavy cruiser of the United States Navy, named for the city of Indianapolis, Indiana.
In 1945, the sinking of Indianapolis led to the greatest single loss of life at sea, from a single ship, in the history of the US Navy. The ship had just finished a high-speed trip to United States Army Air Force Base at Tinian in the Northern Mariana Islands to deliver parts of Little Boy, the first nuclear weapon ever used in combat, and was on her way to the Philippines on training duty. At 12:15 a.m. on 30 July 1945 the ship was torpedoed by a Japanese submarine and sank in 12 minutes. Of 1,195 crewmen aboard, approximately 300 went down with the ship. The remaining 900 faced exposure, dehydration, saltwater poisoning, and shark attacks while floating with few lifeboats and almost no food or water. The Navy learned of the sinking when survivors were spotted four days later by the crew of an aircraft on routine patrol. Only 316 survived.