If you are still in the Mexico city, looking for somewhere to visit, but you don't have enough money or time, I simply recommend Palacio Postal (old post office).
http://www.palaciopostal.gob.mx/main.html
It's across the park in front of Hilton.
https://www.google.com.mx/maps/place/Palacio+Postal/@19.4356136,-99.1408024,...
... And it has majestic architecture. Entrance is free (it's a post office still working!).
Read BBC Travel article for more details.
http://www.bbc.com/travel/story/20140218-voices-of-mexico-city
--Takashi [[User:Takot]]