Sinking civilian ships without warning (un-restricted submarine warfare).
Germany's submarine warfare was unrestricted. These attacks led to World War I.
unrestricted submarine warfare
Germany's unrestricted submarine warfare
unrestricted submarine warfare
Submarine Warfare
German submarine warfare
unrestricted submarine warfare
After the Lusitania incident in 1915, Germany promised to restrict its submarine warfare and adhere to the principles of unrestricted submarine warfare only under specific conditions, which included warning ships before attacking. This promise led to a temporary easing of tensions and allowed U.S. manufacturers to continue supplying goods to the Allies, as they had increased confidence in the safety of transatlantic shipping. However, the eventual resumption of unrestricted submarine warfare in 1917 ultimately pushed the U.S. closer to entering World War I.
Germany's unrestricted submarine warfare
WW1 introduced submarine warfare, tanks, chemical warfare, and aerial combat. Man's history already knew battleship warfare from Tsushima in 1905; and massed land warfare consisting of infantry. WW2 REFINED submarine warfare, tanks, and aerial warfare; chemical warfare was outlawed by treaty.
the Germans' use of unrestricted submarine warfare