Since this is a non-dive-related question, you might get more responses on a general travel forum, such as Tripadvisor's forum or Lonely Planet's Thorntree forum. What would I do if I had 22 hours in Mexico City? Hmm. I like to eat. I'd eat a lot of tacos from the street vendors! I'd stay somewhere central--pick a hotel in the Roma or Condesa neighborhoods, which are sure bets for comfort and convenience. Take a taxi over to the Zocalo or main square and walk around. Stop to eat somewhere. Visit the archaeological excavations/museum there. If you like to walk, you could walk one way or even both ways to/from hotel to Zocalo. Sights along the way would include the Bellas Artes building, parks, etc. If you have time, visit Chapultepec Park, which is a really nice and very large city park. That's more than enough to keep you occupied during a 22-hour layover.
