|I've now been to several ruins, which are in no short supply, and Chichen Itza is the best by far. This site has been partly restored by archaeologists using the original stones, and it is amazing to see them in their former glory (well, the main pyramid anyway).
To get the most out of our experience, we hired a certified tour guide, who gave us a great deal of information. It appears the main reason for Chichen Itza's status as a member of the "seven new wonders of the world", along with the Great Wall of China and The Taj Mahal, is the main pyramid "El Castillo". This one building is effectively a calendar and can be used to predict reoccurring astrological events, such as how long until Venus is visible - once every 200 years for 17 seconds! It also has the most amazing acoustics, able to magnify the voice of a single priest standing at the top so that it could be heard by masses gathered at the base. Apparently the design on the stairways act as funnels for sound, something we witnessed to our amazement and delight as our guide clapped his hands several meters from the start of the stairway.