Winter hit Modena hard in 1898. This small university town, straddling the ancient Via Emilia, was choked with snow the day Enzo Ferrari was born, 18 February. His parents had to wait two days before they could walk to the county hall to register his birth. It was an inauspicious start for the man who would bring more fame and wealth to Modena than anyone before or after (though Luciano Pavarotti did his bit, as did the inventor of balsamic vinegar, though history doesn't record his name).

There's no evidence Enzo was born in a manger, though the modest Ferrari farmhouse was arranged in conventional Italian fashion - livestock on the ground floor, the family upstairs. It was a fitting birth for a man who became so idolised that he was once called "the Pope of the north".

This is the birthplace of an automotive engineer - not, ordinarily, something of interest except to the most hardcore of petrolheads. But unlike many entrepreneurs, who ditch their provincial towns for the big smoke, Ferrari kept his business at home: first in the centre of Modena, then 10 miles down the road in Maranello, where every Ferrari is still manufactured to this day. The story of how he created one of the most glamorous car marques in the world is woven into the story of 20th-century Modena. And yet, until last week, with the opening of the Casa Museo Enzo Ferrari, it had never officially been told here.

Modena has no airport, but Bologna lies just 23 miles to the south-east, and its airport is conveniently located on the Modena side. A bus takes you to Modena every two hours, and takes less than an hour. But this is Motor Valley, home not just to Ferrari but Maserati, Lamborghini and smaller marques like Cisitalia. Of course I need a car. So I hire a Fiat Brava. Driving on Italian motorways can feel like the Monza Grand Prix, no matter what you're in.

I'd like to say I chose to take the Via Emilia, the ancient slow road, to Modena. In fact, I ended up on it as a result of a signreading mistake, but I'm glad I did: this straight-line Roman artery is vital to understanding the layout of the area. The plains of Emilia-Romagna are spread between the Po valley to the north and the Apennines in the south;this road cuts right through the middle, heading south-east out of Milan to the sea at Rimini. Renaissance cities - Piacenza, Parma, Modena, Bologna - are dotted along it with gratifying regularity.

Modena today looks rather different from the one Enzo Ferrari would have seen on entering the world. And that's largely thanks to him: car dealerships and industrial estates - with dozens of factories making automotive parts - now surround the town. But the centre remains unaltered: a pentagon of pretty arcaded streets centring on the piazza, with its 11th-century duomo and Ghirlandina Tower. The duomo is particularly gorgeous, with an untouched Romanesque interior. While most Italian cathedrals underwent a neo-classical or Baroque makeover, they never got around to it here, so all the interior arches are simple and made of red brick. Outside, one of the door arches has one of the earliest tellings of the tale of the Arthurian knights.

Modena's motoring conversion didn't properly begin until after the Second World War. The first car to bear a prancing horse badge appeared in 1947. Biographers can't agree why or when the young Enzo decided he wanted to build racing cars, though in 1903 his father bought a single-cylinder De Dion-Bouton, one of only 27 private cars in Modena registered at that time. Aged 20, Enzo went to find work at the Fiat works in Turin. He failed, and a lifelong resentment towards Fiat was born. After a series of odd jobs, he joined Alfa Romeo as a test driver, graduating to be a racing driver throughout that sport's most heady and dangerous decade, the1920s. He then steered towards the business side, opening Alfa Romeo dealerships in Bologna and Modena.

Much has been written about Ferrari's determination to be the best. Anecdotes tend to portray him as a genius or a monster. Enzo had a reputation for pushing drivers to their limits. After being told of a crash that killed the driver Eugenio Castellotti, Enzo is said to have replied: "And the car. . . ?"

These stories, and many more, have filled biographies, and there is a museum dedicated to Ferrari by the factory at Maranello. But inevitably it tends to focus on the cars. For most, seeing the glorious machines is the main attraction of a visit to Motor Valley. And yet central to Ferrari's story is that he sold his family home to finance his ambition.

The good news is that it survives. For years it fell into decay, and was rented out as garaging, while squatters lived upstairs. It remains in private hands, but a consortium of investors persuaded the owners to convert it into a museum. And it's here that the story stops being about cars to become one about architecture.

In 2005, a competition to redesign the site was won by Future Systems, the London-based firm founded by Czech-born architect Jan Kaplicky. His buildings include the controversial media centre at Lord's Cricket Ground and the futuristic Selfridges building in Birmingham. Both make use of sleek curves. He impressed the judges with his idea of creating, alongside the old house, a new exhibition hall sculpted to look like a piece of a Ferrari. In 2009, when building was about to begin, Kaplicky died of a heart attack, aged 71. It was left to his protêgê, Andrea Morgante, to complete the project, imagining how his mentor would have proceeded.

The results are astonishing. This part of town is quiet and suburban, and as you walk up the footpath towards the original farmhouse, little prepares you for the joyous explosion of undulating yellow roof round the corner. Bright yellow is, of course, the background colour to the Ferrari logo, which Enzo chose as homage to Modena's town colour. The wall of the new building that faces the old is a sweeping curve of glass, which half-envelopes the farmhouse's gable end.

"The facade is quite unique, " says Morgante, showing me how they used yachting technology to support the glass on tensioned stainless steel rods (he wanted to use Kevlar, but the fire brigade said no). The real jaw-dropper is the roof, which looks like a giant carapace. This is no bricks-and-mortar affair: the structure is an all-aluminium semi-monocoque shell, like a boat or a plane. "We found a boat-builder, " says Morgante, "who patented this system of creating aluminium extrusions, with tongue and groove clamped together to create any shape. All this despite our ridiculously low budget of just 14m!"

As the museum does not own any exhibits, it will borrow from private collections in the area. "The content will change every six months, " says Morgante, "because we want people to keep coming back. "

Modena has never been a tourist destination before: the hope is that the Casa Museo Enzo Ferrari will change that. "Italy has always struggled with modern architecture, because we are so blessed with wonderful buildings, " says Morgante. "This was meant to provoke. We wanted to park a huge flashy car in front of an ordinary house in a supertraditional town. "

And if anyone would approve of that, it's Enzo Ferrari.

THE INDEPENDENT