The sacred site of Chichen-Itza in Mexico was one of the greatest Mayan centres of the Yucatán peninsula. In it's 1000 year history, it's been handed around a bit. As a result it shows off Mayan construction techniques with new elements from central Mexico. If you've made the climb to the top. Good on you, you very fit person.
A visit to one of Mexico's ancient sites is a nice complement to a relaxing beach vacation. There are several well-preserved sites and this guide to the Riviera Maya ruins should help you decide which site fits in best to your vacation itinerary.