What a hot topic for rec.boats, 2007.

A 15th Century Turkish navigator produced a map that accurately
depicted
not only the not-yet officially "discovered" Atlantic coastlines of
North and South America, but also the Antarctic continent in an ice-
free state that last existed about 6000 years ago. Piri Reis claimed
that some of the source material for his map came from the libraries
of Alexander the Great, dating those documents to a time about 1800
years before Columbus sailed to the West Indies.

http://www.world-mysteries.com/sar_1.htm