On 14 October 1939, under the command of Günther Prien, penetrated Scapa Flow and sank the First World War-era battleship anchored in Scapa Bay. After firing its first torpedo, the submarine turned to make its escape; but, upon realising that there was no immediate threat from surface vessels, it returned for another attack. The second torpedo blew a hole in the "Royal Oak", which flooded and quickly capsized. Of the 1,400-man crew, 833 were lost. The wreck is now a protected war grave. John Gunther in December 1939 called the attack "the single most extraordinary feat of the war so far".