During World War II, Plymouth was one of Britain's principal naval dockyards, and this naval tradition continues to the present day. Plymouth was extensively blitzed during WWII, to the extent that approximately twice the amount of housing stock that existed prior to the war was destroyed during it (as a consequence of rebuilt houses being successively hit). Although the dockyards were the principal targets, civilian casualties were inevitably very high indeed.
Plymouth was also one of the principal staging posts for the Normandy landings in June 1944.
See also Plymouth England