Manaus is an interesting city, in that it's a big, metropolitan city with a population in excess of two million, and it's not really connected by road to the rest of the country. Transportation in and out is by air or river, unless you want to drive north to Venezuela, and who wants to do that?
BR-319, which connected Manaus to Porto Velho, and via there to the rest of the country, was completed in '73, but within fifteen years most of it had decayed to the point that it was only passable with serious off-road vehicles, leaving only about a hundred miles at either end paved and passable.
The middle stretch is home to some pretty lawless stuff...
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