On a sunny Paris morning I met with a group for a "Da Vinci Code" walking tour in front of the famous Ritz Hotel in the Place Vendome -- notorious now as the last revolving door Princess Diana went through before her death.

It's also well-known as the hotel in Dan Brown's novel, "The Da Vinci Code," where Robert Langdon was staying when awakened and brought to the Louvre by the Judicial Police of Paris to view the crime scene of the death of Jacques Sauniere, curator of the Louvre museum.

Our group of eight consisted of a man from New Zealand, named Mike, who had let his wife have her morning of shopping (they were in Paris for her 40th birthday), a Canadian couple, a young Japanese girl also from Canada, a couple from Australia, my traveling friend Patti, and me.

The Da Vinci Code Walk seemed an interesting and unusual way to fill a Paris morning. Most of us on the tour had read the book once, probably a year ago. But Mike had read it three times.

Our tour guide, Mary Beth, was from the U.S. The tour this morning was smaller than usual, she said in her Texas drawl.

First, thanks to Mary Beth's narrative, we imagined Robert Langdon awakening, and leaving the Ritz with Lieutenant Collett. Then we walked toward and entered the Jardin des Tuileries (Paris' answer to Central Park) by following Langdon's path. It was a great way to see the gardens -- to view the yellow and orange tulips, but also to see in the distance the Arc de Triomphe built by Napoleon and the beautiful avenue, the Champs-Elysees.

Robert Langdon would not have been able to drive through the gardens at night though, as in the novel, our guide said -- simply because the gardens are locked at night.

We headed straight for the western end of the Louvre Museum - toward the giant stone archway of the Arc de Triomphe du Carousel -- and on our way Mary Beth pointed out that two other museums can be seen from the Tuileries Gardens -- the Musee d'Orsay, and the Musee du Jeu de Paume, with its ancient obelisk of Ramses. But though in the novel it says it is possible to view the Pompideau Center (the Museum of Modern Art) as well, she added that it cannot be seen from the garden because of higher buildings.

Soon we were near the Louvre, and Mary Beth pointed out a small brass circular plaque in the pavement, which said "Arago" (for Francois Arago, a French astronomer), one of 135 markers installed in 1994 that signify the Rose or meridian line that runs through Paris, and which was used to designate time in Paris until 1884 (all time is now related to Greenwich time in England).

Entering through the nearby side entrance, we saw the inverted pyramid. Langdon follows the markers to this site, where the meridian line passes beneath. At the end of the novel he believes the bones of Mary Magdalene rest inside a vault beneath the small stone pyramid on the floor beneath La Pyramide Inversee.

The pyramids at the Louvre, inside and out, were designed by architect I.M. Pei in 1989.

We then headed across the Pont des Arts for a spectacular view of the Seine, through the gallery district of the Left Bank, past the Church of St. Germain-des-Pres, before reaching our final destination -- Saint Sulpice Church.

This church, the largest in Paris next to Notre Dame, houses the last frescoes of Eugene Delacroix, and also has a visible brass line in the marble floor of the sanctuary -- again, referred to in the novel as the Rose line, or meridian line. On the summer solstice, light falls on the plaque at the beginning of the line inside the church, where it angles across the floor to the Egyptian obelisk to the left of the altar and moves up 33 feet.

We looked up on both sides of the sanctuary and saw the round stained glass with the letters PS as part of the design. In Dan Brown's novel, this is said to stand for Priory of Sion, an organization holding the secret of the Holy Grail. However, the church explanation is that the initials stand for Peter and Sulpice.

It is here in the novel that Silas, the albino monk, comes looking for the Holy Grail, where he mistakenly believes it to be hidden. He encounters Sister Sandrine and ultimately murders her.

On a wall plaque to the left of the altar, a posted disclaimer reads "Contrary to fanciful allegations in a recent best-selling novel, this is not a vestige of a pagan temple. No such temple ever existed in this place. It was never called the Rose Line. It does not coincide with the meridian of Paris."

The tour ended here -- and we were directed back to the Louvre and to the Ritz Hotel areas, with brochures in hand describing the paintings and areas in the Louvre, where we could trace "The Da Vinci Code" on our own.

We could then see where Sauniere was murdered, and view the Caravaggio painting that he pulls from the wall to set off the alarm; the Mona Lisa (decoded from Sauniere's message, "Oh, lame saint"); and the Madonna of the Rocks, where Sophie Neveu finds the key.

Some headed back to our meeting place, but five of us thought of a different quest to go on -- a quest for crepes! With a suggestion from Mary Beth, we found La Crepe Rit du Clown on Rue des Canettes.

Then we parted ways.

Flying home, I vowed to reread the novel, to bring the experience even more to life.

Crossing the Atlantic now with the recent memories of the tour, the visit to the Louvre, I glanced at the empty seat next to my window seat.

The friend I was traveling with had changed her seat to a nearby aisle seat in order to have more leg room.

A copy of a book titled "Mary Magdalene" lay on the empty seat.

I glanced at the woman, sitting in the aisle seat next to it.

"Is that a fictional book of Mary Magdalene, or a biography or history?" I asked.

A history, she said, and as we began to talk, I discovered she had led spiritual tours in both Sedona, Ariz., and in France -- and in fact, she had led her own Da Vinci Code tours.

I glanced out the window.

Maybe the story wasn't over. The quest was following me.

I was still on this mysterious tour.

Fast Facts:

Classic Walks Paris - www.classicwalksparis.com

Da Vinci Code Tour is 20 Euros, or approximately $35