Welcome to Mammoth Cave. It's 1840 and my name's Stephen Bishop. I'll be your guide, so come with me, by the light of my lantern, into the deepest biggest cave in all of the United States. Down here, beneath the earth, I'm not just a slave. I'm a pioneer. I know the cave's twists and turns. It taught me to not be afraid of the dark. And watching all these people write their names on the ceiling? Well, it taught me how to read too. Imagine that. A slave, reading. But like I said, down here I'm not just a slave. I'm a guide. I'm a man. And this is my story.