It was a bad year for submersibles. In 1968, four separate submarines from different countries completely disappeared. There was the USS Scorpion (U.S.), the INS Darak (Israel), the Minerve (France) and the K-129 (Soviet Union).
Theories around the unrelated disappearances vary, from accidental torpedo self-firing to attacks kept under wraps by the government (particularly between the Scorpion and K-129). All four missing subs still have no explanation, and considering how deep the potential remains could have sunk, an explanation might never arrive.
It was a bad year for submersibles. In 1968, four separate submarines from different countries completely disappeared. There was the USS Scorpion (U.S.),