The Lusitania was built as the 1st of a 3-ship service along the North Atlantic passenger service as British competition to the new fleet of German ships that were beginning to have a dominating presence trade. The brainchild of the Cunard Line's chairman, Lord Inverclyde. He approached the British government to finance the plan with the idea of easy conversion into auxilary cruisers which appealed to the Parliament.
The Lusitania and her sister, the Mauritania were designed by the naval architect Lenoard Peskett as the ultimate ships. The Lusitania was built by Cunard's long time shipbuilder's, John Brown & Company and launched on June 6, 1914 by the widow of Lord Inverclyde. With a crowd of more than 20,000 watching the festivities. Everyone expected Britain's new queen of the seas to be perfect. She wasn't.
During sea trials a fatal flaw was found. The stern vibrated at high speed to the point where it became effectively unusable. So the entire section that consisted of 142 2nd class cabins was gutted and bolted down, delaying everything by 1 month, but it had to be done. Finally on September 7, 1907 the Lusitania embarked on her maiden voyage.
Although she did not win the Blue Riband as Cunard hoped she would on that voyage, she was able to achive it the following month and held it until it was taken by her sister ship, the Mauritania in 1910. From then on till the outbreak of the Great War the Lusitania and Mauritania were a dominanting pair of ships, both in elegance and in speed.
When World War I came in August 1914 the Lusitania continued to serve as a commerical liner with the mindset that she was too fast, and too swift for any German U-Boat to sink her. That mentality ended on May 1, 1915. Nearing the end of voyage she was sailing near the Old Head of Kinsale, against military orders to keep away from shore.
At around 1:20 PM the U-20 spotted the Lusitania and fired a torpedo. There might have been a chance it was avoided, but the warnings from the crow's nest were dissmissed. As the torpedo hit it kicked up the coal dust and caused a huge explosion that caused the ship to list rapidly to starboard. In less than 18 minutes the Lusitania had sunk to the bottom of the English Channel literally pushed down by her still functioning turbines. She took down 1,195 passengers with 764 survivors. Amazingly, there were no lifeboat drills held and many passengers reported milling about the upper decks without knowing where to go.
Today the Lusitania is caught in a web of fishing nets due the shallow water it's in, if that's not bad enough, the Admiralty used it as a testing site for depth charges! She has been visited several times by both American and British teams, including one led by Dr. Robert Ballard. The German Imperiator was given to Cunard as compensation for the Lusitania following the end of World War I and renamed the Berengaria.
Ballard, Robert. Exploring the Lusitania. Italy. Warner Books, 1995