growing unease, a fear that this long—running conflict with russia will soon move closer to home for millions more people. but for now, the theatres fill and the streets bustle. the city on alert, but not alarmed. it was the week that changed the world — or certainly the world as we knew it then. 50 years ago this week, the former us president, richard nixon visited china. the visit is remembered for an opening made possible by ping—pong matches between the us and china — and for the subsequent economic and political impact of the talks. we're joined now by professor margaret macmillan, author of "nixon and mao: the week that changed the world" — and a foreign policy scholar to put that event 50 years go into context. wonderful to have you on the programme. why don't we start by putting that event into