|Can't climb the pyramid at Chichen Itza. It's too touristy now and they have a bunch of new digs going on. It's really cool though and they have a neat night show that talks all about the site and shows the equinox light up. However if you travel a bit further north, you can climb all over Palenque. That area of Mexico is gorgeous. I recommend a full tour of the archeological sites in the Yucatan.