To me, Berlin is as much a conceit as a reality. Why? Because the city is forever in the process of becoming, never being, and so lives more powerfully in the imagination.

Berlin is all about volatility. Its identity is based not on stability but on change.

Berlin inspired Bowie and stirred him to write about real, important matters.

Eight months after graduating from Ryerson, there I was in West Berlin working with Marlene Dietrich and David Bowie and Kim Novak.

Bricks and mortar Berlin has become a kind of network across which visitors and residents interact as if on some sort of comfortable global platform.

London has always moved and surprised me, reinventing itself in ways both fresh and familiar. It's a contrary, complex and creative city, an anarchist of a thousand faces - fickle and unfailing, tender and bleak, ambitious and callous.