El Cathedral Metropolitana: This is in fact the biggest church of Latin-America. The cathedral is damaged by subsidence, in fact the whole city is build on the soft ground of the Lake of Texoco.
This is a magnificent building. The Spanish used bricks and walls from the Aztec temples and pyramids which were located next to the Cathedral (now Temple Mayor). On the right of the Cathedral, there is the Sagrario Metropolitana, a small parish church, with a beautiful front. The interior of the Cathedral is also very beautiful. Especially the Altar de los Reyes is certainly a "must see".
Near the Cathedral, at Monte de Piedad, you can see a row of men. These men all represent different professions like electrician, painter, plumber, bricklayer.
So in fact it looks like a public Interim office. If you need a certain job to be done at your home, over here you can rent a handyman. I believe this is really practical.
Metro : Zocalo