Tristan Hughes

And so how powerful and significant does Greek Pestum, does Poseidonia become?

Pestum was one of many ancient Greek cities in Magna Graecia that has become prosperous by the 5th century BC.

Others included Syracuse and Akragas in Sicily, the latter famous for its own valley of temples at today's Agrigento.

There was also Regium at the toe of Italy, Tarentum at the heel, and of course Neapolis beneath Mount Vesuvius.

We know it today as Naples.

At the same time that famous Greek cities on the mainland like Athens and Sparta were fighting off the Persians and reaching their zeniths, these Greeks in the west were enjoying their own golden age.

Greek culture was thriving in southern Italy, and during these centuries, you would see a special development of Greek art in these cities, influenced by powerful Italian neighbours.

Like the Etruscans, who at that time were still the dominant power in Italy.

Rome, at that time, still paled in comparison.

Visit somewhere like the National Museum of Archaeology in Naples today and you can see great examples of this Italiot Greek art.

But the art from Pestum is particularly special.

Pestum has treasures that are as rare and as beautiful as anything from ancient Greece, with one particular example standing out above all others.

It was discovered one and a half kilometres south of Pestum, not in a grand temple, but in a tomb.

It's called the Tomb of the Diver, after one of the most stunning pieces of ancient Greek art in the world.

A wall painting, rectangular in its design, that depicts a very unique and tranquil scene.

A young man who has just jumped off a tall platform, caught in a perfect dive position, moments away from hitting a pool of water beneath him.

Today, this painting has become a symbol of Pestum and the ancient Greeks in Italy, on display at Pestum's Archaeological Museum.

I was lucky enough to see it up close with Tiziana as my expert guide.

I mean, Tiziana, I have to say, this is one of the most incredible wall paintings I've ever seen.

The details that survive, I mean, it's astonishing.