U-20 fired a single torpedo into the Cunard liner Lusitania as it sailed from New York to Liverpool, and a second internal explosion sent the ship under in eighteen minutes. Among the 1,198 dead were 128 Americans. Germany had warned travelers of the risk in newspaper ads, but the sinking became a rallying point for U.S. entry into World War I two years later.
Captain Walther Schwieger of U-20 had already used most of his torpedoes and nearly let the Lusitania pass when he spotted her four funnels rounding the Old Head of Kinsale. He fired one shot. Survivors and later investigators long debated the mysterious second explosion that doomed the ship so quickly — coal dust, the boilers, or the undeclared munitions in her cargo hold, which the German embassy always insisted were there.
The ship went down in just eighteen minutes, too fast for many lifeboats to be properly launched; several capsized as they were lowered, spilling passengers into the cold Atlantic. Among the dead was theatrical producer Charles Frohman, who reportedly quoted Peter Pan as the water rose: 'Why fear death? It is the most beautiful adventure in life.'
The sinking did not immediately bring America into the war — that took nearly two more years and the resumption of unrestricted submarine warfare in 1917 — but 'Remember the Lusitania' became a potent recruiting phrase, printed on posters showing a drowning mother clutching her infant.