There're three basic limitations of scuba diving.

We need helium, and the helium is what we really need to go deep.

And this rig was actually used for a dive of 300 feet.

The original octopus idea was conceived by cave diving pioneer Sheck Exley as a way for cave divers to share air while swimming single file in a narrow tunnel, but has now become the standard in recreational diving.

But we got up there, and I had the unique and wonderful scientific opportunity and personal opportunity to get to a place that had never been dived and just get to an island and go, Okay, where are we going to dive?

And we developed techniques to dive inside and under the iceberg, such as heating pads on our kidneys with a battery that we dragged around, so that, as the blood flowed through our kidneys, it would get a little boost of warmth before going back into our bodies.

I had never heard of the islands 10 years ago, nor the country, Kiribati, that owns them, till two friends of mine who run a liveaboard dive boat in Fiji said, Greg, would you lead a scientific expedition up to these islands?