"Île Sainte-Marguerite, FranceJust off the coast of Cannes in the Mediterranean Sea, the small, forested island of Sainte-Marguerite—about two miles long and a half-mile wide—was home to one of history’s most enigmatic prisoners. The convict, whose identity was concealed behind what was most likely a black velvet mask, was brought to the island in 1687, during the reign of Louis XIV, and locked up in the Royal Fort, then a state prison. (His barren cell can still be seen.) Later, he was moved to the Bastille, where he died in 1703 at around age 45. The prisoner’s identity and the reason for his incarceration are still not known. But over the centuries, they have been the subjects of much speculation. One popular theory, that he was an older brother of Louis XIV, became the basis for Alexander Dumas’ classic tale The Man in the Iron Mask. The Royal Fort continued to be used as a prison until the 20th century. Today it houses the Musée de la Mer, devoted to marine archaeology."