“You can’t use an old map to explore a new world.”

Years ago we were walking through the Doge’s Palace in Venice and stumbled into the Map Room where, as far back as the 16th century, the Serenissimo Principe could view the vast reach of his Venetian empire.

I got close to one of the two huge globes set into ancient rollers, and saw the crude outlines of what is now North America. Inching closer, I spie…