Your new series. Exploring India's Treasures with Bettany Hughes, is very different to your last one. How did it come about?

We were asked to do it by [commissioning editor] Shaminder Nahal at Channel 4, who is as passionate about India as I am; I've been travelling there for decades. She said India cannot be contained in a single hour, so let's have something more narrative-based and regional. We've done North and South India in this series; the hope is we'll do East andWest next.

It's got ‘Exploring’ in the title, and the idea was to cover some of the household names but try to do them in an unexpected way. With the Taj Mahal, we started in