Pompeii, famously, is the city that was destroyed and embalmed when the volcano Vesuvius erupted in 79 AD. Visiting there, which I did in September with someone I know well, is awe-inspiring, heartbreaking, breathtaking - and there's much more to say too.

But there was another city that Vesuvius also destroyed, nearby Ercolano (Herculaneum). It was much smaller than Pompeii, and so today is a far more compact archaeological site. In both cities, several houses had elaborate, beautiful mosaics on the walls and floors. That these have survived for 2000 years is a story in itself.

The eruption killed people in both cities. Unlike at Pompeii, Ercolano's residents did not die because rocks and soil from the volcano rained down on them. They were killed by a fast-moving blast of hot gas - 400C and 100mph. Because few rocks fell on Ercolano, the buildings were not badly damaged. And after the gas, the town was swiftly buried under hot ash. Result: we have an archaeological treasure of buildings that are both relatively intact and better preserved than at Pompeii.

But also better preserved are the bodies of many of Ercolano's residents. Hundreds of them ran to the beach that day, hoping the sea would offer an escape route from the fury of Vesuvius. Women and children crowded into boathouses on the shore, while the men ran about on the beach, likely trying to arrange some kind of way out. But the gas caught up with them all.

How do we know this? Because while excavating Ercolano, archaeologists found dozens of male skeletons lying on the shore, and hundreds of skeletons of women and children in the boathouses.

Two thousand years later, you can see the skeletons in the boathouses - well, plaster replicas, but they drive home the point pretty well - and somehow that long-ago eruption doesn't seem that long ago. Somehow they give this monumental tragedy shape and immediacy.

Still, if tragic, what happened in Ercolano and Pompeii is also a a great boon to archaeologists and historians today, because they can reconstruct what life was like at the time. And what they found on that beach is a reminder that even with an enormous calamity overhead, there were people trying to save others.

On to Florence, and nearly 2000 years later. Of course it is a city with plenty of famous art - Michelangelo's David, for one.

But it is also a walkable city, and we did a lot of walking. One evening, that's how we heard the mellifluous strains of opera arias. Like moths drawn to a flame, we followed them to a corner of the Piazza della Signoria, expecting to find somebody playing recorded music ... and on a verandah there, we found two young singers pouring their hearts into their songs. No, not recorded! Torna a Sorriento (Come Back to Sorriento), Brindisi from Verdi's La Traviata and more.

And we walked more, and we looked down every now and then, and that's how we found occasional small metal plaques embedded in the pavement. Each remembers a resident of Florence who was murdered during the Holocaust.

Eighty years later, simply standing there looking down at these squares can still give you a jolt ... and then you walk some more and on the famous Ponte Vecchio, you find yourself looking up at a plaque on a wall. This one remembers Gerhard Wolf, German consul in Florence during World War II.

Why the small square plaques for Nazi victims, but also this one for a Nazi officer?

Because in a regime drenched in blood, a world turned upside-down, Wolf held on to some humanity. As his own Army withdrew from Florence, it planned to blow up the bridges across the River Arno, to slow the Allied advance. The people of Florence appealed to Wolf to save at least Ponte Vecchio. Which he did. And still more remarkable is that he also saved several of the city's Jews from death at the hands of his Nazi colleagues.

To honour Wolf, the city of Florence embedded this plaque on the historic bridge. This is what it says:

Gerhard Wolf (1886–1971). German consul, born at Dresden - subsequently twinned with the city of Florence - played a decisive role in saving the Ponte Vecchio (1944) from the barbarism of WWII and was instrumental in rescuing political prisoners and Jews from persecution at the height of the Nazi occupation. The commune places this plaque on 11 April 2007 in memory of the granting of honorary citizenship.

On finally to Rome, and nearly all those two thousand years back in time. A boy was born in that city in 121 AD, and he was seen as special from a very young age. How do we know this? Because when he was just 17, the then Roman Emperor, Hadrian, did something most unusual. He named his successor, Pius - but also Pius's successor: this 17 year-old boy.

And when Pius died 23 years later, the boy - now a 40 year-old man - became Emperor Marcus Aurelius.

Aurelius had his victories in war, as other Roman Emperors had too. But he was probably marked as special - and seen that way even today - not so much because of his military prowess, but because of the way he thought about life. He was a "stoic" - people who followed an ancient philosophy that values reason and logic, virtue over pleasure, austerity over the trappings of wealth, human relationships over power. All of which is why he was known as the "Philosopher King", and is counted as one of the "Five Good Emperors" of Rome.

That stoic outlook on life, Aurelius captured in a famous book called Meditations.

One evening in Rome, we joined a most interesting tour. Our guide, Massimo, took us to various spots in Rome connected to one or the other Roman Emperor, including Aurelius, introducing them to us as the people they were. I took along my copy of Meditations, hoping I could persuade Aurelius to sign it. When I realized he is long dead, I got Massimo to sign it.

And I want to end this by sharing with you a few words from Meditations. Two thousand years later, they mean something to me and, I hope, to you.

Marcus Aurelius sought always "to give to others readily, to cherish good hopes and to believe that I am loved by my friends."

That's good enough for me.