Exactly 150 years ago, another insider account captivated the nation by exposing the secret inner workings of the White House. That one was from seamstress Elizabeth 'Lizzy' Keckley, a former slave who became Mary Todd Lincoln's dressmaker.
Some of these 'un-discovered islands' are products of myth and legend like the famous Atlantis. Others have more unexpected origins like fraud. And a few actually were once considered real by scientists and geographers as recently as this decade.