20 Questions is a simple two-player game in which player A thinks of an object, a place or a person and player B uses a maximum of 20 questions to determine what, where or who it is. Player B must ask only yes-or-no questions, and player A must answer all questions truthfully. If player B guesses correctly before using up all 20 questions, he or she wins the game.
The game of 20 Questions originated as a parlor game in America. It gained prominence in 1946, when it was used as the format for a radio show called "Twenty Questions." Then the TV series "Twenty Questions" followed in 1949, running on various networks until 1955.