This may sound like an odd post but here goes: Rio is the first place on our trip where we are constantly mistaken for locals.
I have to say it is really nice, and it also makes me feel safer (not that we feel unsafe to begin with). I cannot say how many times I have been asked for directions on the metro on in the street. Of course, the illusion disappears the minute I start speaking - my Portuguese is atrocious, and limited to about three sentences!
Brazil is such a melting pot of ethnicities, and it really is a truly multicultural society. Rio has no ethnic neighborhoods at all, people just mix. It is very cool. (Now I hear someone saying hey wait a minute what about the favelas - and that is a good question. The favelas are more defined by economic status than ethnicity - they are poor neighborhoods.)
And of course there are rich neighborhoods as well - every big city has those. In Rio the rich areas are mostly by the water - along the beaches and by the big lagoon. The favelas are on the slopes, with great views across the city and towards the sea - locations that would be super prime real estate in many other cities.