Bus for 435p ($35 US), our money going fast on transport but very comfortable and I've never watched so many movies in such a short space of time...toilet on board as well.
Stayed in Hostel Catadral...right across from Cathedral and eat great breakfasts looking out over the city and plaza (huge cement area, not like most others in Mexico...made from stones that came from the Aztec temple which stood on/near where the Cathedral now stands).
Went to Teotihuacan, huge (see pics)...up to now we have met travelers from Switzerland, US, Germany, Holland, Spain, Canada, and Australia. Actually, one couple we met from LA area was in Glacier Park this past summer on the first weekend they opened Going to the Sun highway (July 4) which is the exact day we went also...and we met them on top of Pyramid of the Sun, can you beat that! How small a world and yet we all live in spheres of different realities...
Mexico City! Sprawling, haze constant from pollution, both of us got coughs! Metro makes it all work, easy and cheap to get around plus to/from bus depots (both) so in and out of city is a snap compared to lots of other big cities in the world!