On this day in 1943 was sunk the SS Dorchester by the German submarine U-223, an example of a fairly regular occurrence in the Atlantic during the Second World War. The Dorchester was a passenger steamship requisitioned for the American war effort and was transporting U.S. troops from New York to Greenland; the whole thing was over very quickly, with the unfortunate result that 674 of the 904 men on board perished. 

Wikipedia.

This episode is famous for the actions of the Four Chaplains, who voluntarily gave up their own life jackets when the supply ran out. They joined arms and said prayers as they went down with the ship. Since that time they have become a symbolic of heroism and self-sacrifice; that two were Protestant, one Catholic, and one Jewish, has become an edifying example of “interfaith in action,” as the postage stamp says. (One could say that this story comes across as propaganda, an attempt at salvaging some inspiration from the usual wartime disaster, but it really happened, and it really is inspiring.)