I read years ago, that the Vikings may have reached as far south as Mesoamerica in their explorations (can't recall the source at all). It was most likely a fantastic statement, but it has grabbed my imagination.

Being a fan of short stories, I have toyed with one where a longship gets that far and makes contact with the natives, then the fate of the crew is to run afoul of the powers that be and wind up as human sacrifices atop an Aztec zigurat !

I am hoping that someday more artifacts will turn up to prove that vikings in fact got further south than N America. It was certainly possible.