Into the Abyss: A Tour of Inner Space

The ocean is such a big part of our world. Still, most of what we know about the ocean we've learned in the last few decades. So why did it take us so long? Fear of the unknown was the major obstacle. Also the lack of suitable equipment kept exploration near the surface. Scientists think rare species live in the great depths of the ocean. But they don't know much more. Some species may even be moving toward extinction. Or maybe they're thriving down in the ocean's deepest reaches -- down in a place called the abyss. The abyss is an alien world full of alien creatures. Let's take a tour.