Petrified Forest National Park, Arizona.
Summer Solstice June 2018
I saw four Solstice rock art sites this year. The best petroglyph calendar I witnessed in action was at Puerco Pueblo in Petrified Forest National Park, Arizona. It is truly remarkable how precisely it animates. A ray of light becomes a snake meandering over a boulder. Just before it reaches the target, the snake extends its tongue and licks the target before its head advances over the petroglyph. The precision of this animation is unbelievable!