carnival balls were hosted in beautiful halls of private mansions and palaces, while blocos ran through the streets of the city.

in modern rio's carnival, both of these worlds cross in the official parades of carnival at the sambódromo.

at these events, one can see the elegance and beauty of carnival masquerade ball wear, with narratives playing out as in an entrudo or bloco.

and in fact, appropriately, the sambódromo is neither a palace or a street, but something in between. 

balls are still somewhat a mostly upper class affair, and in the sambódromo parades are regulated and in competition with one another - thus limiting their social commentary.

at the official parades the political and satirical side may not be as apparent as in the streets, but blocos are free for all, and have no rules or competitions to follow - and that makes blocos ever more special.