The "Missionaries and Cannibals" problem is a classic river crossing puzzle involving three missionaries and three cannibals. The goal is to transport all six individuals across a river using a boat that can carry only two at a time, without ever leaving a group of missionaries outnumbered by cannibals on either side of the river. To solve the puzzle, players must carefully plan each crossing to ensure that at no point do the cannibals outnumber the missionaries. This requires strategic thinking and problem-solving skills, making it a popular exercise in logic and game theory.