The Dance of Light and Shadow, a documentary
by Ray Urbaniak

The sacred rock art images interacted with shafts of light and shadow cast by the sun on rock surfaces. These light and shadow movements of the sun were sacred to the ancestral Puebloans of the southwest USA, including what is now called Utah, Arizona, New Mexico, and Colorado. The sun's path across the sky was studied and tracked in order to make a permanent record of the solstices, equinoxes, and cross-quarter days and times on rock faces.

Many panels also faced the rising sun on these dates, and were the viewing points for horizon markers where the sun came up or set in notches on the horizon.(...) The light and shadow events marked the seasons when to plant and harvest, recording migrations of animals, as well as when to conduct sacred ceremonies to honor the sun and keep the world in balance. This is especially true for the winter solstice so that the sun would not go any farther south and start returning to a position higher in the sky and bring back the spring, a time of abundance. They would also pray that the sun did not go any farther north on the summer solstice or the world would be thrown terribly out of balance.

These ceremonial practices are still observed today by some tribes such as the Hopi of Arizona.(...) Solstice and equinox markers of various kinds can be found around the world, such as in England, Ireland, Scotland, Germany, Peru, Mexico, and Egypt.

Besides the sacredness of the light and shadow on the rocks, the markers probably also served as entertainment.(...) In a time long before books, radio or movies, the light show, along with storytelling and games, were part of their amusement.