buildings have continuing histories -- good histories and bad histories: of modification, of abuse, of renovation. We are trying to embrace the full complexity. The 70s saw the emergence of other prominent architects -- however, their work is different from yours, for example Zaha Hadid's ... I think she is interested in a particular kind of architecture and she is doing it in an impressive way. I have more hesitations, or more competing interests, that probably lead me to a more sceptical way of approaching architecture. I am less focused on aesthetics and more interested in engaging different languages. A very important part of my architecture is that it is deeply engaged with engineering. If you see the CCTV project in China, in particular the interiors, there is an astonishing amount of visible engineering, almost like sculptures in the room. You have witnessed the creation and development of our current understanding of the notion of sustainability. How do you see it has progressed? I was educated within an eco-friendly and sophisticated understanding of sustainability. Buckminster Fuller (an American theorist, architect and futurist renowned for his concerns about design in relation to the resources of the Earth, mainly materialised through the development of geodesic domes) described the earth as spatial and I think it is a good metaphor because it indicates that everyone is in it together. Architecture has a very intelligent tradition, starting with the Romans, of thinking about the issue of how not to waste effort and matter and