This is a series of 4 (I only fit 3) panels of Diego Rivera, probably the most famous Mexican muralist. If you really like Diego Rivera, walk over to the Zocalo and go to the Palacio Nacional, where there are many more of his murals up on the second floor over looking the courtyard. He is amazing and his murals are so full of details that every time you see them it is like looking at them for the first time. This one (like all of his murals) is a critique of society, and he has given the press and politicians animals faces. See the 2nd and 3rd picture down for close-ups.
This view is to give you an idea of how big the murals are. The next picture is the same mural, closer up.
I'm pretty sure this mural is by Orozco (he, Diego Rivera, and Siqueiros are the 3 most famous Mexican muralists and all have murals here in Bellas Artes). If I remember correctly from Tonio's many tours with me, this is a picture of the Spaniards torturing an Aztec Emperor (by burning his feet or burning him at the stake) so that he would tell them where the gold and riches were. The woman on the right is Malinche, who (at least according to legend) was Hernan Cortez's translator, and may have betrayed the Aztecs and thus helped in the Spanish Conquest of Mexico.