There are colourfully dressed assistants in the curious shape of the Swiss Guards with their medieval plus fours, Asterix helmets and pikes. And there is even a post office counter selling stamps which, unlike their Italian equivalents, get your postcards back home before you.
Yet the Vatican is much more than another of those toy-town countries or tax havens like San Marino, the Isle of Man or Monaco which make a living out of their own small-is-beautiful curiosity value. This is God's business address on earth, headquarters of a multinational with branches all over the globe and one billion members.
Moreover, the cosy, familiar face the Vatican presents to outsiders, epitomised over Easter by the sight of Pope John Paul II blessing the world in his urbi et orbi address from a balcony high above St Peter's Square, belies what goes on within the castellated, Caramac-coloured walls that protect the "private - staff only" parts behind the shop-front.
In Rome to research a book about a rather controversial pope back in the ninth century, I spent a good deal of my time trying - largely unsuccessfully - to persuade the Vatican, with its vast archives on matters papal, to co-operate. In the process I was afforded a rare glimpse into the workings of the inner sanctum and realised that it is, once you get under its skin, nothing like a shop-front. Rather it is a fortress whose defenders regard everything to do with the modern world - including secular writers - as a threat and an invasion.
For three decades, since the great reforming Second Vatican Council of the mid-Sixties, the Catholic Church and the Vatican in particular have been working towards making the Church a full and relevant, though critical, presence in the 20th century. This was the aggiornamento - or letting in of the daylight - the concept that inspired Pope John XXIII, the driving force behind the council. Today the shutters he raised have come down. Behind them the Holy See is once more blindly and foolishly luxuriating in being a world apart.
You can see this determined retreat from all things contemporary most clearly in the haughty manner of the young priests and trainee priests around the Vatican and in the streets of Rome. Fifteen years ago, when I used to spend my student summer holidays working there, most of the priests on the streets were kindly, humble men, with either eyes downcast or a friendly, almost regretful smile in the manner of our own Cardinal Basil Hume. They mixed with the crowd. They were, in some unspoken way, of the people. Always, for instance, ready to lend a hand if you lost your way, ever eager to lean over and start a conversation, they might even give your rusting car a push-start if asked.
A few remain but they are a dwindling bunch. Today's generation of priests is just as visible - the worldwide vocations crisis appears so far to have left the first city of Catholicism immune - but the men have changed. Something in the way the Church's future leaders move makes clear at once that they regard themselves as belonging to a caste apart and above. Eyes up, chests thrown out in self-importance, they cold-shoulder anyone who does not wear their uniform.
On one level it is simply a symptom of the return under this pope to a more hierarchical church. They are the living embodiment of one of John Paul II's favourite descriptions of his own priesthood - to be of a sign of contradiction in a secular age, the subject of his 1976 book Sign of Contradiction. He has the charisma and maturity to carry it off. Whatever you think of his views, he is patently a man who carries God in his shadow. But this new breed of brash young priests are already emptying pews in the West at an alarming rate.
Heaven only knows what inner self-image or mistaken training leads these young priests to adopt their aggressive swagger. Most evidence from seminaries suggests that, at a time of dwindling vocations in the developed world, the priesthood has a growing and disproportionate appeal for unhappy young men ill-at-ease with themselves and their own sexuality. If it is true, it will only serve further to disconnect this next generation from the laity.
Behind and above the shop-floor of the Vatican are the offices, depositories and staff accommodation that make up the rest of the Vatican City State. Carved out of the north bank of the River Tiber in 1929, this geo-political anomaly was in effect compensation given by Mussolini for the seizure of papal lands during the reunification of Italy in 1870. For almost 60 years successive popes had locked themselves away in the Vatican Palace behind Saint Peter's in an almighty sulk, refusing to acknowledge the new Italian state. By giving them their own tiny enclave of temporal power in the heart of Rome, Il Duce managed to hitch the Church's spiritual dynamism to his Fascist bandwagon.
Plain curiosity about what goes on in the Vatican is not a good enough reason to be allowed in by the border guards at the Porta Sant'Anna, the one chink of light in the protective walls. You need a higher purpose to talk your way into one of the most closed countries in the world.
In truth, I had only half an excuse. The book I was working on was about the decidedly dodgy subject - in Catholic terms at least - of the legend of Pope Joan, the Englishwoman who according to a heavenly host of medieval writers disguised herself as a man and tricked her way into the papacy in the ninth century. It is hardly a subject designed to make clerics in this all-male club roll out the red carpet. Only lavish reference to a previous incarnation as editor of the Catholic Herald prevented me being sent packing from the Vatican's version of Checkpoint Charlie.
The price of entry was that I had to leave my notebook and tape recorder behind on the other side of the wall. Despite setting up the improbably named Pontifical Commission for Social Communications in theory to free up access to any Vatican site, the Holy See remains somewhat touchy about opening themselves up to scrutiny.
Even a request from a children's pet programme to film the pigeons in Saint Peter's Square is said of late to have been refused by the commission. Yet once I had no means of recording their thoughts for wider broadcast, there was no shortage of eminent and learned Monsignori willing to talk about anything - off the record of course. The Vatican has long been a court of gossipy eunuchs. Some even felt there was something in the legend of Pope Joan and most at the very least knew of, and were amused by, the tale.
They wouldn't, of course, dream of saying so in public. The commission would be down on them quicker than a plague of locusts. It appears to enforce its will not by respect but by fear. At first I thought it was fear of the commission itself. Then I spoke to its likeable head, the American Archbishop John Foley. He is charming, witty and genuinely appears to understand how the press can be worked to the Vatican's advantage. Left to his own devices, I'm sure he would grant much greater access since he realises the damage to the Church's reputation that repeated refusals to co-operate can cause. But he is not one of the inner circle running Catholicism. He is on the next rung down the ecclesiastical ladder of preferment.
Pope Joan does, of course, touch directly on that most sensitive of Catholic nerves - women priests. No matter that she dressed as a man to be pope, some Catholic feminists see her as a rallying point and are fond of remarking that she was not deceiving God and was therefore part of His divine plan.
But the climate I encountered in the Vatican during my research is more than simply a reaction to my chosen specialist subject. No matter what you are talking about, if you are an ordained or salaried member of the Catholic Church, you have to watch your Ps and Qs. The party line is now set out in exhaustive but precise detail in the Catechism of the Catholic Church, some 3,000 rules and regulations about what it is to be a member of this club, published at the Pope's own insistence in 1993. Break the rules, bend them even, and it will not just be ten "Hail Marys" in the confessional.
That such a drive to turn otherwise intelligent men into pre-programmed automatons should be taking place in the Church is profoundly misguided. It has, arguably, only survived because inspired and inspiring individuals down 20 centuries have been prepared to challenge current orthodoxy, step out of line and move it forward. Now to dissent is to risk exile and unemployment.
The Church is not the only organisation which imposes a vow of silence on all but a few chosen spokesmen. There are many multinationals, governments and political parties that aspire to total control. Yet where most off- message Labour backbenchers now laugh at the prospect of Millbank's wrath, those affable Monsignori who could not go beyond a private chat tremble in the face of the Vatican machine.
They have seen too many of their colleagues hauled up before the old Holy Office, once the organiser of the Inquisition, today renamed the Congregation for the Doctrine of the Faith, but still up to its old tricks. A mild-mannered and often quite opaque book about women who seek ordination has recently caused the British radio nun, Sister Lavinia Byrne, to suffer the wrath of Rome. Cardinal Paolo Arns, leader of the Church in Brazil, the world's biggest Catholic country, intellectual and charismatic priests like Hans Kung, Charles Curran, Raymond Hunthausen and Leonardo Boff, the martyred Archbishop Oscar Romero of San Salvador - all have, to different degrees, felt the weight of Rome's disapproval because they did not conform with the prevailing mood in the Vatican.
There is a terrible irony in the fact that a church headed by a man who refused to keep quiet about totalitarianism in his native Poland is fast becoming a totalitarian organisation itself. Indeed the regime John Paul II presides over is every bit as intolerant and brutal in its treatment of those who voice their opposition to its policies as the Kremlin.
Much of Catholicism's recent popularity in attracting Western converts from Anglicanism has been founded on Pope John Paul II's rejection of the moral relativism of late-20th century ethics in favour of a more enduring black and white code of rights and wrongs. But those at the Vatican with day-to-day responsibility for running the Church have taken this basic philosophical message and turned it into a practical crusade of intolerance and introspection.
Today's Rome is a tale of two cities, neither of them particularly alluring. The capital of Italy is increasingly European, cosmopolitan, consumerist, espousing generally secular values with that added Roman menefregismo - literally "I don't give a fuck-ism". If it had its wits about it, the Church would be out there pushing its alternative to these soulless pursuits, but instead, in the heart of Rome, the capital of Catholicism is arrogantly inward-looking, judging anything that is new as bad. It is in mortal danger of turning itself from a living, vibrant spiritual organisation which still has so much to recommend it into a museum-piece with only curiosity value - and stamps - to offer tourists
`The She-Pope' is published in paperback by Arrow on 1 April