Lusitania docks at New York in 1909.

Robert Ballard, an American oceanographer and underwater archaeologist whose claims to fame include discovering the wreck of the Titanic, explores the sunken Lusitania in an attempt to solve the mystery of the second explosion. Ballard finds that the wreck, which lies in just 295 feet of water, has been damaged by previous visitors, including Irish Navy ships who apparently used it for depth charge practice. Ballard finds no evidence that the second explosion was caused by munitions in the hold. Instead, based upon the lumps of coal that he finds scattered on the sea bed around the ship, he theorizes that the U-20's torpedo struck one of the Lusitania's coal bunkers and kicked up clouds of coal dust that were subsequently ignited by fire.

Two years later, after a newspaper reports that a Lusitania passenger, Sir Hugh Lane, may have been transporting paintings by Rubens, Titian and Monet in sealed lead tubes, the Irish government will declare the wreck and historic site under the National Monuments Act, which prevents it from being disturbed for 100 years. In 2006, a diving team from the Cork Sub Aqua Club explores the Lusitania and photographs 15,000 rounds of rifle bullets from the bow section of the ship. In March 2007, the Irish Supreme Court grants American businessman and diving expert Gregg Bemis, who is the legal owner of the wreck, a license to salvage and sell objects from the Lusitania in order to finance an in-depth exploration of the site.