The River Crossing Puzzle is a classic problem in recreational mathematics and logic. It typically involves a scenario where a person must transport a group of items across a river using a boat. The challenge lies in the constraints, such as not leaving certain items alone together, which could lead to undesirable outcomes. In a common version, the person must transport a wolf, a goat, and a cabbage without leaving the wolf alone with the goat or the goat alone with the cabbage. The puzzle requires strategic thinking and planning to successfully get all items across the river without any conflicts.