The Lusitania made her maiden voyage in 1907. When she was sunk in 1915, the ocean liner was on the return leg of her 101st roundtrip voyage across the Atlantic.
In early May 1915, several New York newspapers published a warning by the German Embassy in Washington, D.C., that Americans traveling on British or Allied ships in war zones did so at their own risk. The announcement was placed on the same page as an advertisement of the imminent sailing of the Lusitania liner from New York back to Liverpool. The sinkings of merchant ships off the south coast of Ireland prompted the British Admiralty to warn the Lusitania to avoid the area or take simple evasive action, such as zigzagging to confuse U-boats plotting the vessel's course.
The captain of the Lusitania ignored the British Admiralty's recommendations, and at 2:12 p.m. on May 7 the 32,000-ton ship was hit by an exploding torpedo on its starboard side. The torpedo blast was followed by a larger explosion, probably of the ship's boilers, and the ship sank off the south coast of Ireland in less than 20 minutes.
It was revealed that the Lusitania was carrying about 173 tons of war munitions for Britain, which the Germans cited as further justification for the attack. The United States eventually protested the action, and Germany apologized and pledged to end unrestricted submarine warfare. However, in November of that same year a U-boat sunk an Italian liner without warning, killing more than 270 people, including more than 25 Americans. Public opinion in the United States began to turn irrevocably against Germany.