Some people believe that there was contact between mainland Asia and the people's of pre-Columbia South America. Could this be disproved by the fact that the indigenous peoples of pre-Columbia society did not have smallpox until the Spaniards came?

by Lovely-Midnight
Mictlantecuhtli

There's always room for discussion, but perhaps the section Historians' views of Gavin Menzies' "1421: The Year China Discovered the World" from out FAQ will answer your inquiry.