The Monty Hall problem is a probability puzzle based on a game show scenario. In the game, a contestant is presented with three doors: behind one door is a car (the prize), and behind the other two are goats. After the contestant picks a door, the host, Monty Hall, who knows what is behind each door, opens one of the remaining doors to reveal a goat. The contestant is then given the option to stick with their original choice or switch to the other unopened door. Counterintuitively, switching doors increases the chances of winning the car from 1/3 to 2/3, making it a classic example of probability theory.