U-Boat warfare by Germany during World War I was a critical component of its naval strategy, aimed at disrupting Allied shipping. This unrestricted submarine warfare sought to blockade Britain by sinking merchant vessels without warning, severely impacting maritime trade and supply lines. The effectiveness of U-Boats initially gave Germany an advantage, but it also provoked significant backlash, particularly from neutral countries, including the United States. The sinking of the Lusitania in 1915, which resulted in the deaths of American passengers, contributed to rising tensions, ultimately driving the U.S. to enter the war in 1917 against Germany.