USS Cyclops (March 4, 1918)

The USS Cyclops, a massive Navy cargo ship, vanished in March 1918 while traveling from Barbados to Baltimore with 309 crew and passengers. Despite extensive searches, no wreckage or distress signal was ever found, making it the largest non-combat loss of life in U.S. Naval history. Its disappearance remains one of the most enduring and unexplained mysteries associated with the Bermuda Triangle, with theories ranging from storms to structural failure.