It is known as the most dangerous sport in the world: Cave diving. On average, 20 divers die each year in caves. The prize, in the Bahamas’ “blue holes” and the Yucatan’s limestone cave systems, are pristine and unexplored environments full of geological, biological, and archeological wonders. This Nova/National Geographic production takes you deep down into earth’s treacherous final frontiers.
This courageous team of biologists, climatologists, and anthropologists ventures into the blue holes – underwater caves that formed during the last ice age, when sea level was nearly 400 feet below what it is today – under two Bahama islands, discovering intriguing evidence of the earliest human inhabitants of the islands, finding animals seen nowhere else on Earth, and recovering a remarkable record of the planet’s climate.