the main character in a story called Ali Baba and the Forty Thieves, from The ARABIAN NIGHTS . Ali Baba sees 40 thieves enter a secret CAVE (= a large hole in the side of a cliff or under the ground) by saying the magic words "Open Sesame", which makes a door in the cliff open. He repeats these words, enters the CAVE, and takes some of the gold that the thieves keep there.