With the current news of the Argentine submarine ARA San Juan missing at sea, I'm reminded of an event that happened when I was a child living in then West Germany.
For a few days it was top of the news. I remember the graphic behind the television newsreader: A silhouette of a submarine against a simple map of the Mediterranean. On March 4th, 1970, the French Navy submarine Eurydice went missing after a dive, and after a search effort, several pieces of the ship were found as was an oil slick. (It was known at the time that something catastrophic happened when a geophysical laboratory registered an underwater explosion.)
The ship's crew all perished. As a matter of fact the French navy lost a submarine two years earlier -- it too sank in the Mediterranean. The Minerve has to this day never been found. I hope the crew of the San Juan is found alive and well.