The film tells the story of a simple man's epic journey through life, meeting historical figures and experiencing first-hand historic events while largely unaware of their significance, due to his low IQ of 75. The film differs substantially from the book on which it was based.
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The story follows the life of low I.Q. Forrest Gump (Tom Hanks) and his meeting with the love of his life Jenny. The film chronicles his accidental experiences with some of the most important people and events in America from the late 1950's through the 1970's including a meeting with Elvis Presley, JFK, Lyndon Johnson, Richard Nixon, fighting in Vietnam, etc. The problem is, he's too stupid to realize the significance of his actions. Forrest becomes representative of the baby boomer generation having walked through life blindly.
Full writing:
http://en.wikipedia.org/wiki/Forrest_Gump