Factual error: The Nina, Pinta, and Santa Maria are shown starting back for Spain at the end of the first voyage. In fact, the Santa Maria had wrecked by this time; the return voyage would be made only by the Nina and the Pinta.
Revealing mistake: At the beginning of the voyage, in the shot where the camera pans around the ships (just after the scene when the sail is being unfurled) we can see a jet airliner contrail mark on the sky.
Factual error: The film makes reference to three voyages, stating that the second voyage was the one in which Columbus fell out of favor; the epilogue says that Columbus took a third and final voyage to America. Actually, Columbus made four voyages. The second voyage tarnished Columbus's reputation, but it was the third voyage which proved to be his downfall.
Revealing mistake: After the camera circumnavigates the "Santa Maria", you can see a modern ship on the sea.