Deep sea wreck divers risk their lives to find the kind of treasure that divers John Chatterdon and Richie Kohler turned up. It was an undocumented German U-boat, sunk just sixty miles off the coast of New Jersey.

Chatterton and Kohler devoted themselves to the mystery of the "U-Who" boat they uncovered. They battled the ocean depths, their own fears, and maritime historians who insisted the sub didn't exist.

Tune in to hear author Robert Kurson of the new book "Shadow Divers" talk about the sub's discovery and the secrets it revealed.

Guests:

Robert Kurson, author, "Shadow Divers" and a contributing editor at Esquire Magazine.