In the Arizona desert, James Turrell is creating one of the most ambitious artworks in American history. This guy acquired an inactive volcano and has been spending decades designing and building light-using art exhibits in it.
When the moon passes overhead, its light streams down the tunnel, refracting through a six-foot-diameter lens and projecting an image of the moon onto an eight-foot-high disk of white marble below. The work is built to align most perfectly during the Major Lunar Standstill every 18.61 years.