📅 On This Day in Military History

February 4

1 event across history

⚔️📍 North Sea and Atlantic Ocean1915

Germany Declares Submarine Blockade of Britain

Germany declared the waters around Britain a war zone, announcing that any vessel — including neutral ships — could be sunk without warning. The policy was a direct response to Britain's own naval blockade of Germany.

Germany's submarine campaign would sink 5,000 Allied ships by war's end, but also provoked American outrage that eventually drew the U.S. into the war.

Outcome

Submarine warfare escalates; 5,000 Allied ships eventually sunk