On the coast of Western Australia, you'll find a strange group of lumpy, shaggy rocks.

Imagine they look a bit like a super-sized piece of ginger root, and there's tons of them,

all laying in the shallow water.

They're called stromatolites, and they're kind of rock, but they're also kind of alive.

They're made of sand, which is not alive, but bacteria which is, and the bacteria produces

a kind of adhesive, a glue, that binds the sand together, and as the bacteria makes

more of this glue, the stromatolite grows bigger, ever so slowly.

These particular stromatolites are thousands of years old.

They represent a species that has been on the planet for three and a half billion years,

nearly as long as the earth has existed.

And they're not alone.

We're surrounded by living organisms that live for millennia, rather than centuries.

The living creatures of deep time.

I'm Dylan Thurus, and this is Alasubskira, a celebration of the world's strange, incredible

and wondrous places.

And today, we're talking to author and artist Rachel Susman.

We'll be talking about a subject that's occupied her attention for over a decade and taking

a tour of the world's oldest living things.

That's after this.

3,000-year-old living rocks in Australia, a 9,000-year-old spruce tree in Sweden, 2,000-year-old

Bau Bob tree in South Africa, and a 43,000-year-old shrub in Tasmania.

Rachel Susman has photographed them all.

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