The RMS Lusitania set sail from New York on April 30th, 1915 carrying passengers and supplies for Britain, though it was secretly transporting munitions. That same day, a German U-boat was ordered to destroy ships in the Irish Channel. On May 7th, the U-boat fired a torpedo that struck the Lusitania, causing a second explosion from the munitions. Within 20 minutes, the ship sank, killing 1,119 of the 1,924 aboard, including 114 Americans. While Germany claimed the Lusitania was a military target, the sinking outraged Americans and contributed to the U.S. declaring war on Germany two years later.