A wishing well is a term from European folklore to describe wells where it was thought that any spoken wish would be granted. The idea that a wish would be granted came from the idea that water housed deities or had been placed there as a gift from the gods, since water was a source of life and often a scarce commodity.
Water was seen to have healing powers and therefore wells became popular with many people drinking, bathing or just simply wishing over it. People believe that the guardians or dwellers of the well would grant them their wish if they paid a price. After uttering the wish, one would generally drop coins in the well.
The tradition of dropping pennies in ponds and fountains stems from this. Coins would be placed there as gifts for the deity to show appreciation. [Source: Wikipedia]
Be careful what you wish for... You just might get it ;-)
