When someone is looking to find spiritual answers, meaning to their life, many seek out physical places that have been defined, sometimes by many generations, as sacred, places believed to have spiritual or even healing power. Such places can be, but are not always, churches, synagogues, or temples. What they have in common is something is there-- a spiritual energy that many find rejuvenating-- and to be honest, some find threatening.
Some such places are along ley lines which stretch around the earth. It is interesting how often churches like San Xavier del Bac were built on what the native peoples considered to be powerful, sacred ground, where they already did their sacred rituals. This could make such sites not so much god defined as rather a product of this earth's natural energy.
Some sites, particularly shrines have been established somewhere because something earlier happened there or someone felt the energy and desired to honor it.
A witch would create such a place wherever she was intending to do sacred work by casting the circle and within that circle would be done her rituals. When the work was finished, the circle would be undone with nothing left to show it had been there.
What might seem inspiring and sacred to one person could be occult and frightening to another. Sometimes sacred places are defined as vortexes, such as Sedona, but many are not well known, not labeled; but those who go there will recognize them, sometimes creating a piece of art (prehistoric ones called petroglyphs), building a structure, a medicine wheel, or just sitting or lying for awhile, leaving no defiling marks behind. Often such places are recognized by many religions but with different conclusions for what they mean.
Because I like to visit places, defined as sacred by others, I have several books telling me where to find them. Some of these places I have spent time when I was seeking spiritual energy. I always go with a feeling of reverence. Some have left me very blessed.
I think if someone is looking to do spirit work on their own, finding or creating such places, places that have meaning to them, is beneficial. Why is it effective? That I cannot answer. At some of the shrines, there will be small pieces of paper or other ways to leave behind requests.
These photos are all from Tucson, Arizona, a place with strong spiritual energy of its own, where many cultures have come together and sometimes not with peace. I am not labeling them because their names are not what is important. You might go to them and feel none of what I do. They are examples of the kind of places that speak to my spirit. Each of us must find our own.