Hello and welcome to the intelligence on Economist Radio. I'm your host, Jason Palmer. Every weekday, we provide a fresh perspective on the events shaping your world.

It's been 30 years since the Tiananmen Square crackdown. The real details have been scrubbed from the record in China, but millions know what happened.

Our correspondents reflect on that horrific day and on how hard China must work to keep it out of the national conversation.

And it's tempting to imagine that requiring immigrants to speak the language of their new home country would lead to more unity.

It doesn't. What might help is giving them more time to learn.

But first... Today marks the 30-year anniversary of the Tiananmen Square Crackdown.

In April 1989, demonstrators, mainly students, began to gather in Tiananmen Square to mourn the death of Huya Bang, a relatively liberal Communist Party leader.

Soon, they began calling for political reform.

The protests spread beyond the city, and the government's patience began to wear thin.

Late Sunday afternoon, military helicopters again flew over the square of heavenly peace,

dropping leaflets, calling on the protesters to leave. Yet, with fists clenched, the students

pledged to stay onto the dead.

In the early hours of June 4th,

Chinese troops rolled into Beijing,

firing at crowds of people who blocked their path.

Hundreds, if not thousands, were killed.

Two of our journalists were there at the time, covering the events for the BBC.

So, James, one of my strongest memories of that time is on the evening of June the 3rd,

when I had got into the Beijing Hotel just near Tiananmen Square.

Simon Long edits our international section.

And I'd come in from the east where the army had turned back,

and there was quite a sort of triumphant move.

...