In Just One Day and Just One Year, you're in all these amazing, different places. Did you do a lot of research for those, or did you actually travel to these places in order to write them well?
I've traveled a lot. It was one of the reasons I wanted to write a book about the transformative power of traveling. And so I had been to most of the major locales in the book—I lived in Amsterdam when I was younger, I've been to India like Willem (even acted as an extra in a Bollywood film).
But I still had to do some research. I knew I wanted much of Just One Day to take place in Paris, but a side of Paris I didn't know, so I spent a few days roaming around the places Willem and Allyson go. I also went to Mexico. I'd been there before as a kid and I probably could've gotten away with going by memory but it was spring break for the kids anyway so I turned it into a holiday/research trip.
Setting is really important to me. It's almost another character. So if I don't know a place intimately, it's hard for me to write it.