instruction:
In this task you will be given an answer to a question. You need to generate a question. The answer given should be a correct answer for the generated question.
question:
The Tower of London, officially Her Majesty's Royal Palace and Fortress of the Tower of London, is a historic castle located on the north bank of the River Thames in central London. It lies within the London Borough of Tower Hamlets, separated from the eastern edge of the square mile of the City of London by the open space known as Tower Hill. It was founded towards the end of 1066 as part of the Norman Conquest of England. The White Tower, which gives the entire castle its name, was built by William the Conqueror in 1078 and was a resented symbol of oppression, inflicted upon London by the new ruling elite. The castle was used as a prison from 1100 (Ranulf Flambard) until 1952 (Kray twins), although that was not its primary purpose. A grand palace early in its history, it served as a royal residence. As a whole, the Tower is a complex of several buildings set within two concentric rings of defensive walls and a moat. There were several phases of expansion, mainly under Kings Richard I, Henry III, and Edward I in the 12th and 13th centuries. The general layout established by the late 13th century remains despite later activity on the site.
answer:
what type of castle was the tower of london


question:
Most archaeologists believe that Machu Picchu was constructed as an estate for the Inca emperor Pachacuti (1438 -- 1472). Often mistakenly referred to as the 'Lost City of the Incas' (a title more accurately applied to Vilcabamba), it is the most familiar icon of Inca civilization. The Incas built the estate around 1450 but abandoned it a century later at the time of the Spanish Conquest. Although known locally, it was not known to the Spanish during the colonial period and remained unknown to the outside world until American historian Hiram Bingham brought it to international attention in 1911.
answer:
what is the lost city of the incas


question:
The United States presidential line of succession is the order in which persons may become or act as President of the United States if the incumbent President becomes incapacitated, dies, resigns or is removed from office. (A President can be removed from office by impeachment by the House of Representatives and subsequent conviction by the Senate.) The line of succession is set by the United States Constitution and the Presidential Succession Act of 1947 as subsequently amended to include newly created cabinet offices. The succession follows the order of Vice President, Speaker of the House of Representatives, President pro tempore of the Senate, and then the heads of federal executive departments who form the Cabinet of the United States, which currently has fifteen members, beginning with the Secretary of State. Those heads of departments who are ineligible to act as President are also ineligible to succeed the President by succession, for example most commonly if they are not a natural-born U.S. citizen.
answer:

who is the fourth person in the line of succession for the presidency