The Isle of Demons appeared on maps of the New World for more than a century. But by the mid-1600s, cartographers made an important discovery: There was no Isle of Demons.

Bermeja, a 31 square-mile island in the Gulf of Mexico first charted in 1539, was only officially marked as non-existent in 2009, following an investigation led by scientists from the National Autonomous University of Mexico in Mexico City.