Marylin Arrigan had never walked a labyrinth before. She had heard of them, but all she knew was that they were circular mazes of some sort and that walking a labyrinth was a kind of meditation. Even so, when her friend Judy O'Brien called recently to ask if she'd join a group of volunteers who were building one in St. Mary's City, she agreed to help out.

The group had mapped out, with the aid of a local engineer, a labyrinth right on the banks of the St. Mary's River in Southern Maryland, the ancient sacred ground of Indians. It was modeled after the one on the floor of Chartres Cathedral in France--a circle 40 feet in diameter with a path that leads to the center, or rosette, and back out again.

Arrigan, 50, of St. Mary's County, brought with her, as requested, some stones that were special to her. "As soon as I started I felt an intensity," she says. "I didn't take breaks. I felt everything had to be perfect."

When they stopped for lunch she walked the labyrinth for the first time. "It was like going into a bubble," she says. "My emotions were very complicated, especially near the rocks I brought."

Back at work after lunch, things really started to get intense.

"Suddenly," she says, "I was in a very bright light. I had a vision of an Indian face with long straight hair, blowing in the wind. He had uplifted arms. He kept telling me to look up. I kept looking up. I was engulfed in light.

"He asked if I was committed to walking the labyrinth. I said 'yes.' He said, 'If you are, you must leave a footprint.' When I got to the center I left two deep footprints. As I was walking out he said, 'Now you are walking out, you must go out in the world and leave a footprint.' "

"We all noticed that Marylin had gotten up to walk," says Pat McKenney, the organizer of the project. "We continued to work. She came up to me after walking with tears in her eyes. She was very emotional, but contained. She said she had just had the most powerful and profound experience of her life. And she didn't know what to do with it."

Arrigan's friend Judy O'Brien, an educator, said that Arrigan had been a little skeptical about the labyrinth but finally agreed to come. "It was clear to me she was very moved by the entire experience. But she was in a state of peace." Later, driving home, Arrigan told O'Brien the whole story about her vision. "This was not a normal experience for her," says O'Brien. "She's Catholic. She doesn't go around talking to Indians."

Arrigan can't explain her vision. "I was in tears on and off. It was like a roller coaster. But toward the end I was very calm, it was like a peace. Like I had a mission."

A volunteer, Carol Davis, took pictures with a digital camera as they were finishing up. Flipping through the images, she stopped, stunned, at a shot of the group. For there, in the center of the picture, was what looked like a brilliant shaft of multicolored light, coming from above and directed exactly at Arrigan.

The labyrinth at St. Mary's City had been several years in the planning. It started after a trip I took to the California health spa the Golden Door. It is a beautiful, peaceful place that stresses meditation as well as physical fitness. This particular year, the center had built a labyrinth, modeled after one that had recently been built at Grace Cathedral in San Francisco. That one had been modeled after the one in Chartres. I was encouraged to walk it by the staff, but it seemed like a ridiculous exercise to me and I begged off at first.

But one staffer kept at me. She said it had had a profound impact on many of the guests who had walked it--even, she emphasized, the men. Just recently, she said, a CEO of a major company had called to say it had completely changed his life.

Finally I was persuaded and ventured up the hill to the circle of live oak trees where the labyrinth was situated. It was a gorgeous day, with the sun dappling through the boughs of the graceful oaks and a gentle breeze rustling through their leaves. No one else was around.

The idea of walking the labyrinth, I was told, was to clear the mind, to calm the nerves, to gain insight. The labyrinth at first glance looks like a maze, though it is different in one respect. It has only one path, which takes you to the center and back. You cannot get lost in the labyrinth. At the center, you meditate or contemplate a question.

I concentrated on my son, Quinn, diagnosed at an early age with dyslexia. At that particular time he was undergoing a battery of developmental tests at Children's Hospital that would determine where he would continue his schooling. I had been with him for the first two sessions, but the last test was postponed until the week I had planned to be at the Golden Door. I considered staying home but my husband persuaded me to go.

So I determined to walk the labyrinth at the exact time he was taking the tests. I walked it slowly so that I could be in there for the whole period of the test, concentrating on him the whole time. After my return to Washington we kept our appointment with the neuropsychologist to learn of the results. Most of those results, as with all learning-disabled children, were erratic, inconsistent and inconclusive. However, the doctor said, brightening, there was one test on which he scored higher than the staff had ever seen--genius level, off the charts. What was that?, we asked.

"The maze," she said.

One of the people most responsible for the recent popular interest in labyrinths in this country--several have been built in the past eight years--is Lauren Artress, canon for special ministries at San Francisco's Grace Cathedral. She had her first experience with it at a workshop in 1985 and it was a powerful one. She later visited Chartres and copied the pattern there to put on the floor of Grace Cathedral; later a permanent one of stone was built outside the church. In her book "Walking a Sacred Path: Rediscovering the Labyrinth as a Spiritual Tool" she calls the labyrinth "an archetype of wholeness" and writes, "Walking the labyrinth clears the mind and gives insight into the spiritual journey. It urges action. It calms people in the throes of life transitions. It helps them see their lives in the context of a path, a pilgrimage."

Advocates postulate that the seven-circuit shape of the labyrinth pathway may help to enhance children's learning capacities--much as listening to Mozart is said by some to have beneficial effects. Judy O'Brien will begin a research project with two elementary schools next spring to test that theory. The children will walk labyrinths on a daily basis and be tested for reading and comprehension before and after.

The labyrinth has been around for more than 4,000 years. The oldest known one is on the Greek island of Crete. The Hopi medicine wheel is a labyrinth design, as is the Tree of Life found in the Jewish cabala. During the Middle Ages, Christians who could not make a pilgrimage to the Holy Land would go instead to Chartres, Amiens and Rheims and go through the labyrinths, usually on their knees. Those who walk the labyrinth today often report that their experience is, in fact, something like a pilgrimage--a pilgrimage to the center of themselves.

Though they were common in cathedrals, the labyrinth has no special religious connection. One person wrote to Artress, after having walked the labyrinth, that "what is most precious to me is that the labyrinth is not attached (necessarily) to a religion but has a wider and more personal spiritual quality. It is not required that one know a certain prayer, have certain parents or be baptized--the only requirement is to put one foot in front of the other."

And the goal, according to Artress, is very simple: "Clarity." She quotes theologian Richard R. Niebuhr: "Pilgrims are persons in motion passing through territories not their own--seeking something we might call completion, or perhaps the word clarity will do as well, a goal to which only the spirit's compass points the way."

Today is the winter solstice. It is also the full moon. At 7 tonight, the Synthesis Center of St. Mary's, a nonprofit health and educational organization, will inaugurate the new labyrinth with a celebration circle around the fire, open to the public. The Synthesis Center, founded by Pat McKenney and Maurine Hogaboom, hopes to sponsor and build a larger labyrinth at a later date. Until then, visitors will be welcome to walk the labyrinth on Sundays from sunup until sundown.

Rarely do a full moon and the winter solstice fall upon the same day. The lunar perigee--the point when the moon is closest to the Earth--falls within the same 24-hour period. It will appear marginally brighter than normal during this time. According to the Farmers Almanac, on another such occasion, Dec. 21, 1866, "the Lakota Sioux staged a devastating retaliatory ambush of soldiers in the Wyoming Territory," a coincidence that to me echoes Marylin Arrigan's Indian vision.

Another one: As I was interviewing Arrigan I was sitting at my husband's desk in his upstairs office, where I rarely go.

As she was telling me about the Indian's command to "leave a footprint," I began toying with a pile of papers and suddenly saw something I had been looking for for almost two years--the program for Barry Goldwater's funeral, which I'd attended. It was an extraordinary ceremony, planned by Goldwater, in which a man had performed a moving Native American funeral flute solo and song and dance. Goldwater had been an honorary member of the Hopi Nation and had a Hopi insignia tattooed on his hand. There was a large picture of him in the program, showing the tattoo. Underneath the picture was inscribed a Native American proverb: "We will be known forever by the tracks we leave."

Members of the Washington Post photo department have examined the pictures of Marylin Arrigan at the labyrinth and declared the apparent shaft of light to be nothing more than "lens flare," an optical effect produced within the camera lens itself. Andrew Davidhazy, an expert on photography at the Rochester Institute of Technology, agreed. "I get a lot" of questions like this, he said. "I got someone from Virginia this week with [pictures of] orbs coming from a haunted house. My position on these things is, if you can't see it, it's highly unlikely that the camera will be able to photograph it."

But there are many things for which science has a ready answer but the human heart cannot so easily dismiss. Arrigan is a devout Catholic. Yet she hasn't decided whether to talk to her priest about her experience. "It's a very intense time," she says. The main thing she has taken away from her time in the labyrinth is that "the message we are to live is very simple, just like the Indian face I saw. The message is loving. When you love deeply and care deeply, then everything falls into place. If you walk this Earth and leave your footprints in love, that's how you make a difference."

Lens flare or spiritual experience? Or both? You decide.

CAPTION: The brilliant shaft of light seemed to be shining directly on Marylin Arrigan. Was it lens flare, or something more?

CAPTION: Coming full circle: The labyrinth at the Golden Door, a spa in California.