Billy and Sally set out on a journey to visit a famous castle, but they both forgot to bring any food, water, or money with them. At the onset of their trip, they saw a beautiful rainbow in the sky which they considered to be a good omen. Fortunately for them, along the way, they found some friendly individuals who offered them some high-calorie treats to eat --- gumdrops and peanut brittle being two examples. At one dangerous point in their journey, they had to pass through a swamp, but fortunately, no alligators were seen. Finally, they arrived at the castle, and after a brief visit there, they left the castle, went to a nearby eatery, and had tuna fish sandwiches for lunch. Where in the world was this famous castle located?
Billy and Sally were children, playing a game of Candy Land.