Boo Valley is the fifth course in Mario Golf for the Nintendo 64. It is located in a valley inhabited by Boos. The course is fairly large at 6,635 yards (6,067 meters). Bunkers are rare and there are only two water hazards in the course. However, due to the number of cliffs, it is very easy to hit the ball out of bounds. When choosing this course in tournaments, "Boo Classic" is misspelled as "Boo Clasic". The sky usually looks very dull and foggy at certain times. Crooked mushrooms appear on the terrain in the background, as well as on the course. On par five holes, the fog increases a lot more, and it begins to rain heavily.
Names in other languages