A trip to Chichen Itza is a must.
Avoid guided tours with their crowded buses that leave you stuck there all day in the baking heat. Instead, rent a car and shop for unique gifts like Mayan dream catchers on the way. The Yucatán’s grandest archaeological site gets hot and overrun every day, but do not let that deter you. The famous El Castillo Pyramid alone is worth the trek. Unfortunately, it can no longer be climbed, but just standing in the shadow of this massive miracle (as of 2007 it is one of the new seven wonders of the world) is an experience. Take your time with the rest of this ancient Mayan city with fantastic ruins and reliefs at every turn, including many temples and the Juego de Pelota. Lots of vendors here sell cool stuff like handmade Mayan masks, so bring cash.