4. USS Indianapolis
The USS Indianapolis (CA-35), a Portland-class heavy cruiser, completed a top-secret mission delivering components of the atomic bomb to Tinian Island in July 1945. On July 30, while en route to the Philippines, it was torpedoed by a Japanese submarine, sinking in 12 minutes. Of the 1,196 crew members, approximately 300 went down with the ship; the remaining 900 faced exposure, dehydration, and shark attacks. After four days, 316 survivors were rescued. The tragedy remains one of the greatest losses of life at sea in U.S. naval history (navy.mil).
