Image copyright AFP Image caption If you stand around long enough, a story begins to take shape

There aren't many cities around the world which have as much to offer the sightseer as Rome. Even after visiting the Colosseum, the Sistine Chapel and the Forum, there are thousands of other wonders to behold. But Rome is also full of statues.

I suppose that over time I will get used to them. They will eventually become so familiar that I will pass them by, the way the Romans do, with barely a glance.

But I am still new to this city and for now at least its statues keep catching my eye.

They are so much part of the fabric of Rome that you are constantly rubbing shoulders with them, glimpsing them through archways or passing them on the piazzas - figures emerging from the realms of myth, faith and history.

Sometimes you can almost imagine that, in their stony silence, they are looking right back at you.

Just along from the spot where I wait for my bus every morning, high up on a wall, there is a larger-than-life St Francis of Assisi.

With a halo hovering over his head, and dressed in a cassock, he looks as if he has just dashed out of the church behind him.

Image copyright AFP Image caption Rome is filled with works of art

But to me at least, the way he raises his arm is slightly unfortunate. It makes me think that the saint might be trying to hail one of the taxis in the square below.

But where would he want to go, I wonder? If he was on business, just up the road to the Vatican, I guess.

But further along the street, there is nothing to distract you from the power of the pieces that stand in the entrance to a palazzo.

Among them, two towering male figures face each other. They are Jesus and John the Baptist, and they are close to perfect - almost touched into life out of stone.

Jesus, dressed in not much more than rags, is bending forward so that John can trickle over his head some water from the River Jordan.

He will stand there now forever, a reminder of the barbarity of the past

Stand there and look hard enough for long enough and you start to feel some of the drama of that moment that is captured, and hangs in the air between the two men.

But of all the statues I have come across in Rome, none has made more of an impression than the one in the Campo dei Fiori.

The square has been a marketplace for hundreds of years, and every day people mill about the stalls that sell flowers and cheeses and much else.

At cafe tables round the piazza's edge you can sit and watch the shoppers in the sunshine. It is a bright, busy, lively place, but looming over the centre of it is an extraordinarily sombre presence.

A huge, dark figure with a terrible story to tell.

It is a statue of the philosopher, Giordano Bruno. He stands above the market wrapped in a heavy cloak. And stares out from under a hood, pulled low over his eyes.

He came from a town in the South, on the plain behind Mount Vesuvius.

He started life, more than 400 years ago, as a friar in a religious order, but he began to think what were, back then, dangerous thoughts. He started to say that maybe ours was not the only inhabited planet in the universe.

He believed that the Earth revolved around the Sun - which of course it does - but at the time, in the eyes of the religious powers in Rome, the things that Bruno said were heresy.

He was interrogated and tried by the Inquisition, and spent seven years in jail.

Image copyright AFP Image caption Giordano Bruno, a martyr in the long struggle for freedom of speech

According to the Vatican's account, for a moment Bruno seemed to waver, and be tempted to accept that he was wrong.

But in his prison cell he somehow found the strength to write a letter to the Pope saying that he believed what he believed, come what may.

And so at dawn on a winter's morning in the year 1600, the prison gates swung open. Through them came Giordano Bruno surrounded by guards.

They had forced a metal gag, like a horse's bit, into his mouth. They had made sure he could say no heretical things as he was marched through the streets to the Campo dei Fiori.

And there, in the middle of the square, he was stripped naked and burnt to death.

I suppose that later that morning the traders just swept aside Bruno's ashes, and got back to business as usual.

But centuries on, his admirers put up the statue in his honour, on the place where he died. He will stand there now forever, a reminder of the barbarity of the past.

The courage he showed when he started writing that last letter is an extraordinary thing. He is a martyr in the long struggle for freedom of speech and thought.

And if you know Giordano Bruno's story, even on the sunniest day, his statue brings a touch of gloom to the Campo dei Fiori.

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