Ali Baba and the Forty Thieves

“When he reached the entrance of the cavern, he pronounced the words, “Open Sesame!” The door immediately opened, and when he was in, closed upon him. He quickly entered and had as many bags of gold as he could carry at the door of the cavern, but his thoughts were so full of the great riches he could not think of the necessary word to make it open. Instead of Sesame, he said, “Open, Barley!” and was much amazed to find that the door remained fast shut. He named several sorts of grain, but still the door would not open.”
–The Arabian Nights, ‘The Story of Ali Baba and the Forty Thieves’