It was a subject [ volcanoes] that was dormant in me for a long time and it popped up 40 years ago when I made a [short] film on the Caribbean island of Guadeloupe about a volcano that was about to explode and a single farmer refused to leave ["La Soufrière"].

I had complete freedom. They [Netflix] knew roughly what I was doing.

You have to realize that, about 20,000 years ago, there was a cataclysmic event when an entire rock face collapsed and sealed off the cave. It's a completely preserved time capsule. You've got tracks of cave bears that look like they were left yesterday, and you've got the footprint of a boy who was probably eight years old next to the footprint of a wolf.

I live my life outside of the glitz and glamour of the red carpet events, and so you’ll never see me there. I’m never at parties.

It's curiosity, and always a sense of poetry. You see it in particular in the chapter "Iceland" where I'm reciting ancient Icelandic poetry. It has this very beautiful gravitas in conjunction with the volcanoes.

I am a product of my failures.

Some of the most important caves, like Lascaux in the Dordogne region in France, have had to be closed down. There had been too many people allowed in, and they left a mold on the walls that is spreading and which can't really be stopped.