USS Indianapolis (CA-35) was a Portland-class cruiser of the United States Navy. She served as flagship for Admiral Raymond Spruance while he commanded the Fifth Fleet in their battles across the Central Pacific. She holds a place in history due to the circumstances of her sinking, which led to the greatest single loss of life at sea in the history of the U.S. Navy. On 30 July 1945, shortly after delivering critical parts for the first atomic bomb to be used in combat to the United States air base at Tinian, the ship was torpedoed by the Imperial Japanese Navy submarine I-58, sinking in 12 minutes. Of 1,196 crewmen aboard, approximately 300 went down with the ship.