Given the question: Information: - Klaus Wennemann (18 December 1940 7 January 2000) was a German television and film actor. - U-boat is the anglicised version of the German word U-Boot , a shortening of Unterseeboot, literally "undersea boat". While the German term refers to any submarine, the English one (in common with several other languages) refers specifically to military submarines operated by Germany, particularly in the First and Second World Wars. Although at times they were efficient fleet weapons against enemy naval warships, they were most effectively used in an economic warfare role (commerce raiding), enforcing a naval blockade against enemy shipping. The primary targets of the U-boat campaigns in both wars were the merchant convoys bringing supplies from Canada, the British Empire, and the United States to the United Kingdom and (during the Second World War) to the Soviet Union and the Allied territories in the Mediterranean. - Sinking of the Lusitania : Terror at Sea ( also known as Lusitania : Murder on the Atlantic , in German : Der Untergang der Lusitania : Tragodie eines Luxusliners ) is an English - German Docu - drama produced in 2007 . This 90 - minute film is a dramatization of the sinking of the RMS Lusitania on May 7 , 1915 by a German U-boat , U- 20 . The outside filming was done in South Africa ; the inside submarine scenes were filmed in Munich using the 25 - year - old U-boat - model of the film Das Boot . - Home video is pre-recorded media that is either sold, rented or streamed for home entertainment. The term originates from the VHS/Betamax era, when the predominant medium was videotape, but has carried over into current optical disc formats like DVD and Blu-ray Disc and, to a lesser extent, into methods of digital distribution such as Netflix, Hulu, and Amazon Video. - Herbert Arthur Wiglev Clamor Gronemeyer (born 12 April 1956) is a German musician and actor, popular in Germany, Austria and Switzerland. He starred as war correspondent Lieutenant Werner in Wolfgang Petersen's movie "Das Boot", but later concentrated on his musical career. His fifth album "4630 Bochum" (1984) and his 11th album "Mensch" (Human) (2002) are the third and first best-selling records in Germany respectively, making him the most successful artist in Germany with combined album sales over 13 million. - A miniseries (or mini-series, also known as a serial in the UK) is a television program that tells a story in a predetermined, limited number of episodes. - War film is a film genre concerned with warfare, typically about naval, air, or land battles, with combat scenes central to the drama. It has been strongly associated with the 20th century. The fateful nature of battle scenes means that war films often end with them. Themes explored include combat, survival and escape, sacrifice, the futility and inhumanity of battle, the effects of war on society, and the moral and human issues raised by war. War films are often categorized by their milieu, such as the Korean War; the most popular subject is the Second World War. The stories told may be fiction, historical drama, or biographical. Critics have noted similarities between the Western and the war film. - Jurgen Prochnow (; born 10 June 1941) is a German-born American actor. His best-known roles internationally have been as the good-hearted and sympathetic U-Boat captain in "Das Boot" (1981), Duke Leto Atreides in "Dune" (1984), the minor but important role of Kazakh dictator General Ivan Radek in "Air Force One" (1997), and the antagonist Maxwell Dent in "Beverly Hills Cop II" (1987). - The British Empire comprised the dominions, colonies, protectorates, mandates and other territories ruled or administered by the United Kingdom and its predecessor states. It originated with the overseas possessions and trading posts established by England between the late 16th and early 18th centuries. At its height, it was the largest empire in history and, for over a century, was the foremost global power. By 1913, the British Empire held sway over 412 million people, % of the world population at the time, and by 1920, it covered , % of the Earth's total land area. As a result, its political, legal, linguistic and cultural legacy is widespread. At the peak of its power, the phrase "the empire on which the sun never sets" was often used to describe the British Empire, because its expanse around the globe meant that the sun was always shining on at least one of its territories. - Das Boot (German meaning "The Boat") is a 1981 German epic war film written and directed by Wolfgang Petersen, produced by Gunter Rohrbach, and starring Jurgen Prochnow, Herbert Gronemeyer and Klaus Wennemann. It has been exhibited both as a theatrical release and as a TV miniseries, and in several different home video versions of various running times. - A blockade is an effort to cut off supplies, war material or communications from a particular area by force, either in part or totally. A blockade should not be confused with an embargo or sanctions, which are legal barriers to trade. It is also distinct from a siege in that a blockade is usually directed at an entire country or region, rather than a fortress or city. While most blockades historically took place at sea, blockade is still used on land to prevent someone coming into a certain area. - Commerce raiding is a form of naval warfare used to destroy or disrupt logistics of the enemy on the open sea by attacking its merchant shipping, rather than engaging its combatants or enforcing a blockade against them. It is also known, in French, as guerre de course (literally, "war of the chase") and, in German, Handelskrieg ("trade war"), from the nations most heavily committed to it historically as a strategy. - Wolfgang Petersen (born 14 March 1941) is a German film director and screenwriter. He was nominated for two Academy Awards for the 1981 World War II submarine warfare film "Das Boot" (1981). His other films include "The NeverEnding Story" (1984), "Enemy Mine" (1985), "In the Line of Fire" (1993), "Outbreak" (1995), "Air Force One" (1997), "The Perfect Storm" (2000), "Troy" (2004), and "Poseidon" (2006). What entity does 'sinking of the lusitania: terror at sea' has the relation 'main subject' with?
The answer is:
submarine warfare