Parable of the Phantom
When the caravan had traveled more than halfway, a great city appeared. The guide told the people of the caravan that here was an opportunity to rest and be refreshed.
After they rested, the guide made the city disappear. He told the people that the city was nothing more than an illusion he had created to allow them to rest. He told them that their goal, the treasure land, is close.
Refreshed, the travelers continued on their journey.