1418 Ming Dynasty map
The map pictured above is said to be a copy of an original 1418 Ming Dynasty map, which potentially proves that in the 15th century, the Chinese were already exploring the shores of modern-day North America. This version was copied in 1763 by artist Mo Yi-tong and was sold for $500.
Read A Review of the Historical Importance of Oldest World Map by Gunnar Thompson, PhD for more information.