It's rather late in the day to point you all out to this, but 40 years ago today there was nasty scene in Mexico City. Go to Machetera and read up about the 1968 massacre of students by the Mexican authorities on the eve of that year's Olympics. It's a sobering--and none too well known--story that is overlooked in the States, but in the context of the times was very important, and shockingly sad. Watch the video too.
And for those of you who have a hard time believing in the incredibly nasty meddling of the U.S. in Latin American affairs, read through the whole thing. It's got some shocking FOIA info that should make your blood curdle.
(To quibble a bit with the article: Echeverría was arrested in 2006 in connection with the massacre, but I believe he was found too old to stand trial.)