Follow Dr. Kenny Broad as he dives into underwater caves that formed during the last ice age when sea level was nearly 400 feet below what it is today. They are Earth's least explored and perhaps most dangerous frontiers. With an interdisciplinary team of climatologists, paleontologists and anthropologists, Broad investigates the history of Earth's climate as revealed in this spectacularly beautiful alternate universe.
洞穴潜水被称为是'极限中的极限',是世界公认的,非常具有挑战性的和危险性的极限运动之一,因为压力的改变对人体生理和神经系统的影响,使得每次探险深度的推进变得异常艰难和复杂。片中的Kenny Broad博士将潜入几处形成于冰河时代的洞穴,那时的海平面比现在要低400英尺。随队的有气候学家、古生物学者和人类学家,他们将探求地球气候的历史。