The CASTILLO at CHICHEN ITZA reflects the amazing skill of engineering calculations and proportional measurements on a vast scale.  An imposing structure, both in mathematical precision and placement.  

The location and alignment of the pyramid were important in the Mayan's solar eclipse predictions with particular regard to the sequence of eclipse (solar/lunar) galactic studies and the movement of planets over the centuries.  The Mayan's ability to predict astronomical events is truly amazing.  It has even been suggested that the pyramid was built for a particular celestial event that is predicted to take place in December, 2012.