The afternoon Sun with some unbeams pointing down to Fajada Butte, at Chaco Canyon, New Mexico, a famous site for archaeoastronomy. Sunlight streaming through the series of layered rocks at the Butte (and not accesible to the public) forms a dagger of light superimposed on a spiral petroglyph, marking the dates of the solstices and equinoxes.
The Amazing Sky 