As per 'Variety', he was quoted telling 'Radio Time UK' during his last interview, I've found spooky things on mountains, when you know you're in a place where many people have lost their lives, whether it be on the Eiger or in the Andes.

He further added You may be confronted with human remains and that can be chilling. It's not necessarily supernatural, it's possibly all too natural - what I would call hypernatural.

You're in the presence of big nature and big nature is revealing itself in all its power. It can take us over a threshold of hypersensitivity into a realm of natural forces.