The Fountain of Youth is a natural wonder that can be very beneficial to all that find it, not only the civilization that manages to include it within its borders. When a land-based military unit moves into a hex adjacent to the Fountain, it gains a special promotion that allows it to heal at twice the normal rate for the rest of the game! Try to make use of this ability as much as possible, sending as many of your units as you can there. If the Fountain gets incorporated into another player's territory, try to get an open borders agreement with him or her so you can continue to benefit from its healing power! This natural wonder is also notable for being the least likely to spawn during map generation.