Richard Nixon's 1972 visit to Communist China to meet Chairman Mao was a "geopolitical earthquake" according to former US diplomat Winston Lord, who attended the meeting between the two leaders.

It ended several decades of wary relations between the US and China that had seen the two countries spar in the Korean and Vietnam wars.

It also succeeded in creating a new balance in the Cold War that positioned China closer to the US.

Equally, it began the long process of opening up China to the outside world after years of isolation, a process that has ultimately led to the emergence of China as a major world power.

Winston Lord spoke to Witness about the historic meeting.

Witness: The stories of our times told by the people who were there.