Since we have a polethora of potato threads right now, how about one not on the potato's global impact but just that of the New World. What if the potato spread out of the Andes and becomes established everywhere that it could be supported by agriculture in South and North America in pre-Columbian times. I'm reluctant to give a specific POD as I don't want to limit the conversation.
So basically the green parts of this map, exclusive to the New World.
So basically the green parts of this map, exclusive to the New World.