Chichen Itza is the most famous Mayan city in the Yucatan Peninsula. It's also in a lot better shape than the other ruins, by a pretty wide margin. I was hoping to be able to climb one of the pyramids as I had done at the ruins in Coba, but unfortunately they no longer allow this. Apparently it was allowed a few years ago but I imagine that there were so many tourists that they had to take measures to ensure the conservation of the ruins.
Chichen Itza is one of the seven wonders of the world and, as you'd expect, if full of both tourists and local vendors hawking souvenirs. My favorite part was the iconic pyramid ("El Castillo" to the locals) which is 24 meters high and has 356 steps.