This thought came to me yesterday.  Quetzalcoatl, aka Kulkulkan was known as the flying serpent god.  Here's a pic:

 

 

 

Now take a look @ the flag of mexico:

 

it's like an homage to Quetzalcoatl, a serpent combined w/ an eagle. 

 

The rattlesnake date is in reference to the Pleiades, they thought it looked like the rattle.  They called it the Tsab date.  Here it is in alignment w/ Chichen Itza:

 

 

 

 

 

 

 

 

and here's yet another reference to quetzalcoatl in a crop circle

 

kari