The sacredness of Chartres goes way back to Neolithic times. The first dolmen was placed atop the mound many thousand years ago to mark the spot where the Great Mother was venerated. Fast forward several thousand years to the time of Julius Caesar. In his Gallic War, he recorded that the Druids established their yearly conclave and Druidical college at the very site. Chartres was then the geographical center of the territory inhabited by the Celtic tribe called Carnutes.
Fast forward again several hundred years to the twelfth century and the erecting of the famous Gothic cathedral at the spot. The cathedral incorporated the ancient dolmen as well as the sacred Druidic well and the early Christian worship of the Black Madonna. It was also built according to the principles of sacred geometry, with a specific purpose of altering the consciousness of those who enter. This was done through the use of precise ratios in elevation and proportions to give the cathedral properties of a tuned, resonant chamber. Add to this the quality of light created by the famous stained glass windows (the alchemical formula for producing those numinous colors has been lost, and never since have those colors been reproduced), and you get the idea why Chartres was the most sacred site in France.
But wait—I forgot to mention the famous labyrinth in the nave … walked by the pilgrims of all ages—at least until recently, when the church authorities put a stop to this meditative practice and covered it by chairs.
Dwight and I had the good luck to be accidentally locked in the crypt below. I say “good luck” because the crypt is not open to individual visits. It was a true gift to be alone there (even if we had to bang chairs on the doors to be rescued). How this happened and what we experienced in the dark place of the Black Madonna worship, you can read in my spiritual travelogue--Meet Me in the Underworld: How 77 Sacred Sites, 770 Cappuccinos, 26,000 Miles Led Me to My Soul.