The clearest example is the Viking presence in Newfoundland. In the 1960s, archaeologists uncovered unmistakable Norse remains at L’Anse aux Meadows. These were turf longhouses similar to those in Greenland, an iron forge with slag, a bronze ring-pin, and signs of boat repair. These finds match the Vinland described in the Icelandic sagas, which speak of a milder, forested coast with wild berries and groups skilled with bows.

Yet, there are also indirect clues. Butternuts that only grow south of Newfoundland were found at the site, suggesting the Vikings travelled further down the coast. Norse goods in the Inuit Arctic show long-reaching trade routes. In 2021, scientists used traces of an ancient solar storm locked in wooden beams to date the start of building at the site to 1021. The settlement probably lasted only ten to fifteen years before being abandoned.

The second possible case is Polynesian. While the archaeology is not fully settled, strong genetic evidence points to contact between Polynesian voyagers and groups on the Pacific coast of South America around 1200. They share distinctive genetic markers, and the Polynesian word for sweet potato, kumara, is almost identical to the Quechua k’umar, which hints at direct interaction.

So much remains unknown about the Precolumbian Americas, so these outside insights are invaluable.