Chaco Culture National Historical Park
The park preserves one of the most important Ancient Pueblo Peoples cultural and historical areas in the United States. Inhabited between AD 900 and 1150, the park is located in New Mexico.
Many Chacoan buildings’ alignment reflect the solar and lunar cycles. It would’ve taken them generations of astronomical observations and decades of skillfully engineered construction to end up with such an organization of their buildings.
The most famous of the Chaco Canyon is the Sun Dagger, a petroglyph crafted to mark the cycles of the sun. Three large stone slabs lean against a cliff, allowing light to cast shadow markings onto two spiral petroglyphs on the cliff wall. These shadows mark the solstices, equinoxes and the lunar standstills of the 18.6 year cycle of the moon. At the summer solstice, the dagger of light pierces the center of the large spiral. At autumn and spring equinoxes, the light strikes the center of the smaller spiral. Two daggers of light seem to bracket the larger spiral during the summer solstice. The sunlight in the form of a dagger steps outward year by year, ring by ring.
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