The objects, buildings and monuments featured in Around the World in 80 Treasures are incredibly diverse. What do they all have in common?
They all tell a story. And the hope was that all these stories would form a greater narrative. For example, many of the places I visited are sacred sites. I suppose that's predictable, because, throughout history, we've built material monuments to the immaterial. But I hadn't realised until I got going just how many were related to the world's great religions and ancient faiths.

Was it difficult to find locations untouched by Western influences?
It's hard to find somewhere without a Coca Cola or McDonald's sign. Or, worse still, that isn't threatened by war. A darker theme which emerged during the series was the fact that ancient ways of life are under threat. We're going to have to fight bloody hard to hold on to special places or to retain ancient believes. In Iraq and Afghanistan, many historic sites are not protected from looting, which is fuelled by a Western black market that has created a huge demand for artefacts.

What were the most memorable moments?
Those occasional locations, often unexpected, when you visit somewhere sacred that remains sacred. The great temples in India, for example, where beliefs go back 4,000 years - older than the Egyptian gods. But those beliefs are still alive, still part of daily life. It was extraordinarily moving to witness history that was fully alive, traditions that hadn't been reduced to themed spaces in museums but were out there on the street, involving thousands and thousands of people.

It must have been a challenging series to make.
It was! Time was limited, so we had to plan meticulously. But, paradoxically, the thing wasn't conventionally scripted. I'd done lots of research, so I had a pretty good idea of what I wanted to say. But most locations hadn't been reconnoitered. I just had to be informed, turn up, respond and be filmed. It was a very spontaneous way of doing television.

So, what make great history television?
You've got to balance the beast that is television - viewing figures, accessibility and so on - with the inspirational, educational, entertainment thing. You've also got to aim for a sense of reality and spontaneity, even though television, by its nature, is all planned out in advance and you often have to do things more than once.

What history programmes inspired you when you were younger?
I liked conventional programmes like Kenneth Clark's Civilisation. Perhaps it seems old-fashioned now, but I was brought up on that sort of television and really admired it. Civilisation was fantastic - straight information delivered with insight. On the other hand, with modern programmes like Around the World in 80 Treasures, you're on an adventure, discovering things and sharing them with the viewer, rather than telling them what to feel. Maybe that's better - I don't know.

If you could have been involved in the creation of one of the treasures you featured in the series, which one would it have been?
Oh dear, that's a difficult one! Maybe Chartres Cathedral. It perfectly combines art with engineering, giving it a tremendously powerful presence, full of all-embracing sacred imagery. At the same time, it's not the building that's important but the space it defines.

When you're not working, how do you relax?
By reading a book, although I haven't done that for ages! My mind is on the go constantly at the moment, which is very stimulating. But I can't quite think what relaxing means these days...