"Ali Baba and the Forty Thieves" is a famous tale from the collection known as One Thousand and One Nights. The story follows a poor woodcutter named Ali Baba who discovers a secret cave filled with treasure, hidden by a group of forty thieves. He learns the magical phrase "Open Sesame" to access the cave and takes some gold for himself. However, the thieves soon realize their treasure is missing and seek to find the culprit. Ali Baba's clever slave girl, Morgiana, plays a crucial role in protecting him and outsmarting the thieves, ultimately leading to their downfall and ensuring Ali Baba's safety.