Teotihuacan was incredible. Amazing scale and a marvel to take in the huge pyramids and surrounding temples etc. our guide Elio(? Not sure on spelling) was excellent - extremely knowledgeable on the history of the site aswell as Mexico culture. I learnt a great deal on both topics and really valued his flexible style and way to explain the histories of Mexico. The only disappointment was that you are now unable to climb any of the large pyramids - this should be explained prior.