Ok fabiana, this one is bit rural african one
You are by the side of a river crossing in the savannah, and there is no bridge or waypoint to cross it on. There is a little boat you can cross the river with, with you, you have a lion, a goat and a bail of hay. Your task is to cross the river with them, but the cunundrum is, you cant leave the lion and the goat at the same side in the same time, because the lion will eat the goat, and you can not have the bail of hay in the same as the goat because the goat will munch on it. You can cross the river with the boat how often you like, but in a way that wont have the above happen.