First time in Mexico in 1990, on a short trip with Klaudi from the USA to Ciudad Juarez (from El Paso). Life was just as different, more like Europe, more colourful, more lively, not so McDoof.
The second time I flew to Yucatan (via Mexico City) with an excursion of the University of Kassel with agricultural students in 2000. There we had a cooperation with the University of Merida. I really liked Yucatan. Were on the Hacienda Hobonil and saw many old Maya things. Was one of the most beautiful excursions.
In 2008 I spent 7 days in Mexico: 5 days in Queretaro (at the IGA 2008) and 2 days in Mexico City passing through Guatemala and Costa Rica in hotels.