Q: What's the difference between a Jehovah's Witness and a Wiccan?
A: Three Watchtowers.
These days witches' circles are often cast complete with invocations to the guardians of the Watchtowers, one in each cardinal direction.
According to researcher John Michael Greer, the Watchtowers most likely entered the Craft from the Golden Dawn, which in turn derived them from John Dee's Enochian magic. During the original Enochian workings, during the 1580s, scryer Edward Kelly had a vision of four great towers at the quarters of the earth, the seats of guardian archangels (Greer 581).
Down the years, the Watchtowers and their guardians have acquired a deal of lore, little of which has anything to do with the original metaphor. But rising above the amassed archangels, elements, and Enochian tablets stands a simple, clear image: an image with implications.