Columbus

[Thunderchild]

I recall that columbus is said to have a copy of the Peris maps before he left europe so realy he already knew america was there ?

[Peter Pedant]

I recall that as well, but that may not er make it true

[jno]

many mysteries about the Piri Reis maps - see here

[kempie]

I thought that he was searching for a western route to India and got it totally wrong, so much so that he thought the mountains on Cuba were the Himalayas, leading to the misnomer of a local island group being called the West Indies.

[Octavius]

History places a great significance on his landing in America in 1492, with the entire period of the history of the Americas before this date usually known as Pre-Columbian.  Besides the fact that there were many instances of Pre-Columbian trans-oceanic contact, and it is questionable whether one person can "discover" a place which is inhabited by other people, Columbus is often credited as having discovered America because his voyage marked the beginning of the Spanish and European colonisation of the Americas.

There are many theories on pre-Columbian contact between continents.  See here