Mass grave for the victims of the sinking of the RMS Lusitania, a passenger ship of the British Cunard Line, which sank off the coast of Ireland on May 7, 1915, after being torpedoed by a German Submarine, U-20. The sinking aroused great anger in the United States, and this contributed to US entry into World War I. The RMS Lusitania was a four-stack passenger ship owned by the Cunard Steamship Lines. Built by the ship-making firm of John Brown and Company, Scotland, it was launched on June 6, 1906, and was one of the fastest ships of her time. She had a top speed of 26.7 knots, with a service speed of 25 knots, and was designed to transport up to 2,198 passengers. In 1907, she won the Blue Ribbon for fastest transit between New York and Britain. In August 1914, the Great Britain declared war on Germany and the Axis powers, and the Germans introduced a new weapon of war, the submarine, to the naval war. While the first submarine existed as early as 1776, submarines were new to warfare in 1914 as it was only then that the technology had advanced sufficiently to make their construction worthwhile. Despite the declaration of war in Europe, Britain continued to transport people between Britain and the neutral United States, for business, vacation, and tourism. Germany warned Americans not to travel on British flagged ships into the war zone declared around the British Isles. International pressure on the belligerents argued that tourist and passenger ships were not to be attacked, only warships and merchant ships carrying arms; the rules required that a submarine had to surface and stop a merchant ship, allowing the crew to get into lifeboats, before sinking it. When British Q-ships (ships posing as harmless merchant ships to lure U-boats to the surface only to sink them with hidden cannons) began making their appearance, the Germans resorted to declaring unrestricted warfare; beginning in February 1915, U-boats were permitted to sink merchant ships without warning. When the U-20 sank the Lusitania at 2:00 pm about ten miles off the coast of Ireland, it fired only one torpedo, yet a second major explosion doomed the ship several minutes later. The Lusitania rolled over and sank in only 18 minutes. The British claimed that the sinking was without warning and on a peaceful passenger ship. Subsequent investigation fifty years later found that the British were transporting nearly 1250 artillery shells and 4 million rounds of small arms ammunition on the Lusitania disguised as boxes of cheese, thus making it a legitimate military target under international rules of the time. The Germans claimed that illegal contraband caused the second explosion, however, most naval experts believe that the second explosion was either caused by exploding boilers or by coal dust in the coalbunkers. Of the 1,969 persons aboard the ship, only 774 survived; for weeks after the event, bodies would wash ashore along the Irish coast. 128 American citizens lost their lives, including Alfred Vanderbilt (millionaire businessman), Anna Marjory Allan and Gwendolyn Allan (daughters of wealthy businessman H. Montagu Allan), Justus Forman (author and playwright), and Frederick Stark Pearson (engineer and entrepreneur). A subsequent investigation into the sinking showed that Lusitania Captain William Turner had failed to order practice lifeboat drills, as required since the sinking of the RMS Titanic several years earlier. Thus, in the short time that the ship remained afloat, few crewmen knew how to launch the lifeboats, and panic ensued on board the ship in its final minutes.