The oceans cover three-quarters of our planet, hiding a whole other world beneath the waves. If we could pull an imaginary plug at the bottom of the sea and, layer by layer, expose the majesty and mystery of what lies beneath, we would be astounded. Drain the Ocean is a Discovery Channel documentary narrated by Avery Brooks, revealing the mountains, plains, canyons and creatures of the deep. It reveals the longest mountain range (65,000 kilometres!); the deepest point on Earth; the largest stretch of flat plains; and psychedelic bioluminescent life forms that look like Hollywood aliens.