A guide to the sites visited by the Oceans team in the Atlantic Ocean. In this episode the team make a dangerous dive into a 'black hole' to discover how different our planet's earliest oceans were 3.5 billion years ago. They dive one of only two places on the planet where the oldest life form on earth still survives. Finally they then brave waters teeming with sharks to act as human bait.

• Mark Halliley
• Philippe Cousteau Jr.
• Paul Rose