"Remember the Lusitania! Avenge the Lusitania!"

These are the words that inspired many young Americans to volunteer for service during the First World War. The sinking of this great British oceangoing liner provoked outrage around the world on an unprecedented scale. On May 7, 1915, a German torpedo sent the ship to the bottom of the North Atlantic Ocean in just 18 minutes -- its speedy descent into the depths occurring far too fast for most of those aboard to make it to the lifeboats. Of the 1,962 passengers and crew on board, 1,201 were lost, including 94 children and, crucially, 128 Americans, many of whom were prominent figures. President Woodrow Wilson's neutral stance started to crack. All over America there were calls for the United States to take up arms against Germany. In many ways, the Lusitania tragedy was the major turning point of the Great War, and perhaps the single greatest factor that eventually brought America into the war in April 1917.

In this dramatic two-hour special, Discovery Channel brings you the story of the doomed ship and, for the first time, goes inside the cramped, foul-smelling hull of the U-boat that fired the fateful torpedo. The central figures in this epic tale are the two men in command: Captain William Turner of the Lusitania and Kapitanleutnant Walther Schwieger of the U-20. The former is a seasoned mariner, but he falls victim to his own arrogance and the Royal Navy's inability to effectively counter the new submarine threat. The German commander is the epitome of the new breed of ship hunters, determined to savage the merchant fleet and warships of the enemy power that has imposed a stranglehold on his homeland. But at a critical moment he learns that some of his crew have no stomach for sinking passenger liners.

Swept up in this cataclysm are the passengers. Having been categorically warned by the German government that all ships entering the war zone around Britain and Ireland are targets, they nevertheless embark; some are unconcerned, others apprehensive. Some passengers openly challenge the captain's lack of interest in lifeboat and lifebelt drills, others discount the mere possibility of an enemy attack. In the end, most become helpless victims of the forces that were dragging the world into total war.

With a superb cast and stunning re-creations, SINKING OF THE LUSITANIA: TERROR AT SEA takes you back to the fateful six-day voyage from New York City to a watery grave eight miles off the south coast of Ireland. The final minutes of the doomed luxury liner are replayed in real time — from the deadly torpedo hit at 2:10 p.m. on May 7, 1915, to the final plunge beneath the waves 18 minutes later.