In Paulo Coelho's The Alchemist, Santiago (the boy) has a recurring dream. He believes it is a dream that portends his eventual discovery of a great treasure, especially after speaking to the gypsy in Tarifa. Santiago assumes (with good reason) that he will find treasure at the pyramids in Egypt (which is the place he sees in his dream). When the young man visits the gypsy, he does not yet know about his Personal Legend, watching for omens or speaking the Language of the Universe. He thinks of the treasure only in terms of financial gain.
However, when Melchizedek (the King of Salem) visits Santiago and explains the concept of one's Personal Legend, the boy begins a journey that he does not quite understand. Santiago believes that he will be wealthy in a worldly way, but the dream symbolizes something much greater: it represents the reward that Santiago will receive if he will stick to his goal to realize his Personal Legend, which will involve watching for omens, understanding the natural world around him (speaking the Language of the Universe) and even connecting with the Soul of the World. While Santiago will eventually find a long-lost treasure, he will find his real reward when he finally understands his place in the world, and falls in love.
The dream symbolizes what we can achieve if we don't lose sight of our hopes and if we don't give up, even when we are tempted to. If a person gives himself (or herself) to the universe, he will be rewarded in enormously significant ways—and financial gain will become secondary.