I think it's pretty certain that the Phoenicians knew the route from the west coast of Africa to the coast of Brazil - shortest route to the Americas.
There was a little publicised discovery of a Roman galley off the coast of Brazil a few years ago. See here: http://www.freerepublic.com/focus/news/1038045/posts
It was deemed too politically sensitive to advertise. To quote:
" So, why haven't we heard more about this fantastic find? One would think this news would make headlines around the world… The short answer is “politics”. At the time the amphorae were confirmed to be "Roman", the large Italian faction in Brazil were extremely excited about this news.
The Italian ambassador to Brazil notified the Brazilian government that, since the Romans were the first to "discover" Brazil, then all Italian immigrants should be granted immediate citizenship. There are a large number of Italian immigrants in Brazil and the government has created a tedious and costly citizenship application procedure for Italians that does not apply to Portuguese immigrants. The Brazilian government would not give in and the Italians in Brazil staged demonstrations. In response, the Brazilian government ordered all civilians off the recovery project and censored further news about the wreck hoping to diffuse the civil unrest. The Brazilian Navy continues to excavate the wreck in secret. "