1939: Europe: THE SQUALUS: 
On May 23, 1939, the submarine "SQUALUS" dived with an air intake valve open. Fifty-nine men were trapped inside and 33 were saved with a newly-developed diving bell. After four months THE SQUALUS was raised and recommissioned as the "Sailfish ". It was one of the Nay's worst peacetime submarine disasters until the "Thresher" tragedy.