ROME, as they say, was not built in a day. Step into the Eternal City and you'll see that it couldn't have been built in 100 or even 1,000 years. The ancient builders have left behind an architectural legacy which has endured over 2000 years - in a city which itself stands as a colossal museum housing masterpieces from the powerful Roman Empire through the Middle Ages and Renaissance, right up to the present day.

The city, after all, was once the centre of western civilisations. The ubiquity of historical sites in Rome is such that with every street corner you turn, you'll inevitably stumble upon some preserved monument; be it a Roman ruin, a sculptured fountain or a grand piazza.

No other monument in Rome is likely to be as recognisable as the Colosseum. Although it's now just a shell of its former shelf, it's still an imposing piece of architecture. We've seen it often enough on TV, photos and of course digitally enhanced as the backdrop for the Russell Crowe movie Gladiator. Even so, you can't even begin to understand the magnitude of the Colosseum until you step into the crumbling amphitheatre and stand under one of its arches towering nearly 50 metres over you.

Next to the Colosseum are the remains of the Roman Forum which was the political, economic, and religious centre of ancient Rome. Tourists are able to make their way through the ruins along Via Sacra (the Sacred Road), the main street in the Forum, which stretches from the Colosseum to the top of Capitol Hill. Near the start of Via Sacra is the oldest surviving arch in Rome - the Arch of Titus. A simple one-opening arch, it's considered to be one of the most well-proportioned of its kind still standing. At the other end of this historical street is another prominent arch - the Arch of Septimus Severus - so impressive it was said to have inspired Napoleon to create the Arc de Triomphe in Paris.

As one wanders through the crowded streets of Rome, one begins to realise that the Romans don't seem to like doing things in half measures - both physically and aesthetically. It's easy to feel small and humbled by the city's main attractions, nowhere more so than St Peter's Basilica, perhaps the largest church in the world, sprawled over 22,000 sq m and capable of hosting 60,000 visitors.

Located within the Vatican City, which is technically another sovereign state, it is 'modern' by Roman standards, with its construction starting in 1506 and eventual completion more than a century later. There are several main elements to visiting St Peter's, with most heading first to its famous square to marvel at the genius of Bernini, creator of the immense elliptical piazza and its colonnades.

The colonnades, which enclose the square, consist of 284 Doric columns (each standing 13m high) arranged in four rows. At the centre is an Egyptian obelisk that was brought to Rome in 37BC, now flanked by two water fountains. Between the obelisk and each fountain are white marble discs which mark the focal points of each colonnade. Stand on the disc and the magic of Bernini will be revealed - the four rows of columns line up to make up only one!

From the square, one also catches sight of Michelangelo's magnificent dome which tops the basilica. There is an elevator within the church which takes visitors to the roof and from there, it's a mere 330 steps to the top of the dome, where you're rewarded with a magnificent view.

Also to be admired inside the resplendent church are works of important artists: the Pieta by Michelangelo, the 29m high bronze baldachin by Bernini, and the mosaic of the Navicella by Giotto.

No visit to the Vatican City is complete without popping into the Sistine Chapel to see Michelangelo's most famous works - the frescoes on the chapel ceiling. The Italian master's brilliant depiction of scenes from the book of Genesis and his painting of The Last Judgement draw crowds to the Sistine like fans to a Rolling Stones concert.

If that has whet your appetite for more art, a tour of the Vatican Museums will more than fill your needs. The Vatican Museums constitute the largest museum complex in the world with one of the greatest art collections.

The collections began in the 16th century and today boast a diversity which includes Egyptian antiquities, classical statues, Etruscan relics, Byzantine paintings, Renaissance masterpieces by Raphael, da Vinci, Titan, and even a collection of modern artists like di Chirico and Rodin.

Finally, weary visitors traipsing through the Eternal City will also soon realise that they are never far from a source of water. They probably don't even realise that the water trickling out from the city's numerous fountains has actually been running for centuries. A clever network of aqueducts has been supplying water to the city since ancient times, and to this day, thirsty travellers can refresh themselves at drinking fountains called 'nasoni' or big noses, named after the distinct shape of the curved spouts.

The most famous fountain is no doubt the Trevi Fountain, immortalised in Federico Fellini's classic film La Dolce Vita. But most won't leave without tossing a coin into it, to test the age-old belief that it will bring them back to Rome.

By nightfall, Rome is transformed into a theatrical stage with the dramatic lighting of its majestic treasures. If its monuments appear huge by day, at night they are simply gargantuan. With strategic lighting and a bit of imagination, you can almost sense a tyrannical Roman emperor and his army of fearless soldiers lurking somewhere in the shadows, waiting to reclaim the mighty city which he once ruled. As I bid arriverdeci to Roma, with still so much to explore, I hope that my little coin in the fountain will work its magic and lead me back to this amazing city.

The author is a freelance journalist based in Italy