The swim at Deception Island was by far the hardest swim I've ever done. Antarctica is a very unforgiving environment. If you don't train properly, you'll die.

On my second swim at Deception Island, the water was very clear and I was looking at hundreds of whale bones beneath me. It was a graveyard from the whaling some time in the 1920s-30s.

The days of exploration of Shackleton and Scott are long gone. Everything has been climbed, crossed, done. Now what we're exploring are the full boundaries of human endeavour. It's not physical - it's all in the head.

We need to save the Arctic not because of the polar bears, and not because it is the most beautiful place in the world, but because our very survival depends upon it.

Finding that balance between work and family is the hardest thing I've ever done - by far.

In the cold, all the blood rushes to your core to protect your heart, lungs, kidneys, liver, and brain. When you leave the water, the blood rushes back to your arms and legs, absorbs that freezing cold, and brings it back to the heart.