Leif Erikson
Leif Erikson or Leif Ericson ( 970 – c. 1020) was a Norse explorer from Iceland. He was the first known European to have set foot on continental North America (excluding Greenland), before Christopher Columbus. According to the Sagas of Icelanders, he established a Norse settlement at Vinland, tentatively identified with the Norse L'Anse aux Meadows on the northern tip of Newfoundland in modern-day Canada. Later archaeological evidence suggests that Vinland may have been the areas around the Gulf of St. Lawrence and that the L'Anse aux Meadows site was a ship repair station.
Luisa Isabel Álvarez de Toledo, 21st Duchess of Medina Sidonia
During her extensive research in the archives she discovered documents which convinced her that America might have been discovered a long time before Columbus by Arab-andalusian or Moroccan sailors trading with ports in Brazil, Guayana and Venezuela and she published her views in "No fuimos nosotros" ("It wasn't us") and "África versus América".