Saturnia
Saturnia or Ogygia is mentioned by Plutarch as being an island around five days sailing west of Britain. He added that at a similar distance westwards from that island, there were the three islands of Cronus, to where proud and warlike men used to come from the continent beyond the islands, in order to offer sacrifice to the gods of the ocean.
There has been no clear identification of this place but understandably has been seen by some as a reference to Atlantis or by others as evidence of contact with North America.