A look at how the role of battleships changed over the course of the First and Second World Wars. At the start of the 20th century, the battleship was the preeminent warship; yet during the Battle of Jutland, it failed to deliver the killer blow. In the waters of Scapa Flow, we find sunken dreadnoughts and tell the story of how a U-Boat sank HMS Royal Oak. On HMS Cavalier, we explore how new technologies such as radar and ASDIC won the Battle of the Atlantic. A daring raid by commandos called Operation Chariot once more showed the vulnerability of the battleship. But on the USS Massachusetts, we discover how the battleship found a new role as a gun platform.