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Big Ben is the nickname for the Great Bell of the Great Clock of Westminster, and, by extension, for the clock tower itself, which stands at the north end of the Palace of Westminster in London, England. Originally named the Clock Tower, it was renamed Elizabeth Tower in 2012 to mark the Diamond Jubilee of Queen Elizabeth II. The clock is a striking clock with five bells.
The Palace of Westminster is the meeting place of the Parliament of the United Kingdom and is located in London, England. It is commonly called the Houses of Parliament after the House of Commons and the House of Lords, the two legislative chambers which occupy the building. The palace is one of the centres of political life in the United Kingdom; "Westminster" has become a metonym for the UK Parliament and the British Government, and the Westminster system of government commemorates the name of the palace. The Elizabeth Tower of the palace, nicknamed Big Ben, is a landmark of London and the United Kingdom in general. The palace has been a Grade I listed building since 1970 and part of a UNESCO World Heritage Site since 1987.
Casting is a manufacturing process in which a liquid material is usually poured into a mold, which contains a hollow cavity of the desired shape, and then allowed to solidify. The solidified part is also known as a casting, which is ejected or broken out of the mold to complete the process. Casting materials are usually metals or various time setting materials that cure after mixing two or more components together; examples are epoxy, concrete, plaster and clay. Casting is most often used for making complex shapes that would be otherwise difficult or uneconomical to make by other methods. Heavy equipment like machine tool beds, ships' propellers, etc. can be cast easily in the required size, rather than fabricating by joining several small pieces. Casting is a 7,000-year-old process. The oldest surviving casting is a copper frog from 3200 BC.