[Alter Kaker]

What I would find interesting is if there were evidence that the Romans or other Mediterranean peoples had knowledge of the Western Hemisphere.

While it's conceivable that at some point, a Roman galley may have been blown across the Atlantic (although, given prevailing winds, it seems highly unlikely), that's a far cry from knowledge of the Western Hemisphere. Ptolemy was the greatest geographer of the classical world, and he had no knowledge of the Western Hemisphere. The Greek, Krates of Mallos, who lived several hundred years beforehand, predicted that North and South America would exist, but not because of any knowledge of them, but because he thought that the world would look funny if there weren't continents in the Western Hemisphere to make the world symmetrical.

[Wallace T.]

Europeans, Middle Easterners, Polynesians, and Chinese may have all reached points in the Western Hemisphere before Columbus. There is no clear evidence that their visits impacted the cultures and languages of the aboriginal inhabitants of the Americas. There does appear to be a Caucasian element in the heritage of some of the natives of the Western Hemisphere, but that could be explained by the fact that there were Caucasians in Northeast Asia, such as the Tocharians of western China and the Ainu of northern Japan, who could have migrated on the same path as the Mongolian groups, rather than attributing these characteristics to Phoenicians, Jews, Romans, Irish, or Scandinavians coming in historical times.

However, there are too many instances of pre-Columbian European and Middle Eastern artifacts in the Americas to attribute to alleged fraud on the part of Spanish conquistadors, English Pilgrims, or Swedish immigrants. Like the moon voyage in the 1960s, some exploration may have been accomplished by Europeans and others, but was not pursued because of its unprofitability.