Ngozi Okonjo-Iweala

Nigeria, with the oil sector, had the reputation of being corrupt and not managing its own public finances well. So what did we try to do? We introduced a fiscal rule that de-linked our budget from the oil price.

When people said Africa would change me, I didn't understand what they meant. To see the poverty in the townships, for instance, is overwhelming. I found it heart-wrenching to see young children walking barefoot and hungry in the dirt. I'm the kind of person who wants to change the world right here and now, so I got frustrated.

When I have a creative insight, there is a high. I think back in the day, I made music as much as I did because it made me feel so good. I think you could argue that there is a creative addiction - but, you know, the healthy kind.