Rory Stewart

And to mark that milestone, they've asked a fitting question.

Of all the moments that define us as a species, from fire to flight, democracy to discovery, I like the alliteration, what's the biggest ever human achievement?

I'd maybe develop that and say underneath that, the biggest ever human achievement, I think, is our ability to actually think about other humans and other species.

We are very, very selfish in many ways of species.

We have a real tendency to be like, let's look after our own families, ourselves first.

But the amazing thing, along with all the damage we've done in the world, is we did have an idea of international development.

we did have an idea of tackling global poverty, of trying to work together on climate change, of setting up democracies where people have equal rights, of having a redistributive tax system where wealthier people contribute to people who are less well-off, of having systems where, in the end, we actually do begin to care about nature, conservation, the environment.

So I think our biggest achievement as a species

is we're not quite as selfish as we sometimes think.

And I think I want to encourage us.

Keep going.

Yeah, we sort of lean into it.

We should lean into our generosity.

Here's a question for you.

How many southern white rhinos do you think there were about 1905?

I've got no idea, Roy.

Okay, answer is about 25.

How many do you think there are today?

More than that.

Yeah, 25,000.