National Geographic World Adventure maps
The Adventure World maps by National Geographic are pretty good. The maps are printed on some kind of thin plastic that doesn't tear and won't turn into a soggy mess if they get wet. Ask me how I know. $11.95 per map. There are maps for most of the big countries, but not every one. They take 7-10 days to arrive if ordered over the internet. You might find them in a good map store.
Adventure Maps - National Geographic Store
Its hard to find maps once you arrive in some countries, so I recommend loading up before hitting the road. Never found one in Guyana, Suriname or French Guiana. I found a few OK maps in Bolivia at magazine/stationary stores and tourist offices.
If you want to start a conversation, just open a map.
NYC to Tierra del Fuego (and back!) 2012/2013
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