Which passenger ship was sunk by Germany in 1915, leading to increased U.S. involvement in World War I?

The Lusitania was a British ocean liner that was sunk by a German U-boat in May 1915. This event had significant implications for U.S. involvement in World War I. The sinking resulted in the deaths of 1,198 passengers and crew, including 128 Americans. The incident provoked widespread outrage in the United States and contributed to the shifting public opinion against Germany, as many Americans viewed the attack as an unprovoked act of aggression against both civilians and neutral parties. The Lusitania's sinking illustrated the dangers posed by unrestricted submarine warfare and highlighted the growing ties between the United States and the Allied powers. Ultimately, this tragedy, along with other factors, played a pivotal role in leading the U.S. to enter the war in 1917.