Winter solstice at Chichen Itza

Twice a year, on the winter and summer solstices, as the sun sets over Chichen-Itza, the ensuing pattern of light and shade and light projects the likeness of the Plumed Serpent (Quetzalcoatl) onto the steps of the pyramid.

Carved illustration of the celestial serpent by Achim Frederic Kiel

On the winter solstice, It takes 34 minutes for the shadow to move from top to bottom along the north west edge of the pyramid, giving the appearance of a serpent slithering down the steps.  On 21 December 2012, the tail of the serpent is expected to point towards the Pleiades star cluster.