Based on your interests, the Museum of Anthropology is your best bet - it is world class. The Zocalo (Constitution Square) is 2nd best for quick hits of several iconic places (cathedral, templo mayor, national govt headquarters).

Both can be reached in less than 30 minutes and will take as little or as much time as you have. Food options are better at the Zocalo.

But it really depends on your response to Londinense's questions and your time factor comfort level. It will take less but plan on one hour to clear immigration and customs and get to ground transportation. You should want to be back in the terminal about 2 hours before your departure - so now you are talking about 4 hours for touristing (2:30pm - 7pm).

If you are adventurous, go visit the city you will love it. But if not, there are some good shops in both terminals - use the neat little aero-train - plus the duty free, enjoy the lounges if you can (AeroMex gives massages!) and there is actually some decent airport food in T2.

excellent and "somewhat" recent but still relevant discussion here: http://www.flyertalk.com/forum/mexic...xico-city.html