The Titanic and Lusitania of the Baltic
From the Royal Navy:
While on operations in the Baltic, HMS Echo mapped two shipwrecks from the Second World War. Using her specialized multibeam echo sounder, the ship was able to show the destruction caused to German ships Wilhelm Gustloff and Goya.
The ships were used in Operation Hannibal – a mass seaborne evacuation of German civilians and soldiers from East Prussia in 1945 during an effort to escape the onrushing Soviet Red Army. Around 16,000 lives were lost when Wilhelm Gustloff and Goya sunk after being hit by Russian torpedoes.