Only a few cases of pre-Columbian contact are widely accepted among the scientific and scholarly mainstream. Maritime explorations by Norse peoples from Scandinavia during the late 10th century led to the Norse colonization of Greenland and of L'Anse aux Meadows in Newfoundland, which preceded Columbus' arrival in the Americas by some 500 years. There is also significant evidence of material exchange between the peoples of Siberia and Alaska dating at least five centuries before Columbus' travels to the New World. Genetic evidence presented in 2020 found that some eastern Polynesian populations have admixture from coastal northern South American peoples, with an estimated contact around 1200 CE.