The feathered serpent of ancient Mexico was a main god in Mesoamerica for most of the 15th century. But when the first Spaniards arrived in 1519 their leader Hernan Cortes, in his shining armor and plumed helmet, looked like the Mexicans had imagined their god. So they revered him and welcomed his army, thus sealing the fate of their civilization.
Here is how the ancient Aztecs carved Quetzalcoatl in stone.
This is how we imagine him today from descriptions the ancients left us.
Knowing the story of the god and the sad mistake by the ancient Mexicans I was eager to visit Chichen Itza when in Mexico to see the famous Mayan pyramid and surroundings. Despite a miserable ride in a bouncing bus and the relentless heat I was not disappointed:
The history and myths are too long and complicated for this post. So if you are not familiar with them I suggest a little internet research. I guarantee you will enjoy the journey to ancient times and culture.
Wikipedia has a very nice summary to get you started: Wikipedia on Quetzalcoatl I recommend this because so many sites about this myth are meager or have copyright requirements. This one has lots of good information and splendid pictures.