One of the most important days of my life was when I learned to ride a bicycle.

As I work in the afternoon on committing to paper some of my morning's thoughts, I find myself just about to close on the knotty question of whether or not I believe in God. In fact I am about to type, 'I do not believe in God', when the sky goes black as ink, there is a thunderclap and a huge crash of thunder and a downpour of epic proportions. I never do complete the sentence.

People look for patterns in everything. It's what keeps us sane, I suppose. I struggle to see any patterns in my life. I think I can understand depression a bit because of my sister. My own feelings of ... I'm aware that, if you feel down, it can be strangely unrelated to circumstances around you. That's just the way life is.

One of the difficult things of so much travelling is to say goodbye.

There are people who travel because they want to push themselves to physical limits, people who walk across deserts or cycle across the Antarctic - like Ranulph Fiennes, who just does it because it's there. And then there are people like me, who are just genuinely curious about the world.

I've been lucky to have made a number of travel programmes with the BBC, the object being to see places off the beaten track. As a result, I've often had a guide who's been able to show me things that you wouldn't see with a tour group.

There are many ways of seeing the world. You can hang upside down from a meteor, volunteer to be the fourth stage of a three-stage rocket, or simply get in a balloon and keep going. But if it's sheer, unadulterated discomfort you're looking for, just stay on land.