Nothing is walkable!’ shouted Flavia Liz from the front seat of our black saloon, responding to a question I always ask when I visit a new city. The driver, Jose Robson, is weaving as best he can through the morning traffic. He’d been held up in the rush-hour and was late to collect me at my remote hotel. Now guide Flavia Liz was anxious for us to get to a gallery on time. ‘I am always punctual. I am famous for it. Ah, look! Stop!’ The poor driver slowed down. ‘That is the modernist house of...’ I’d no idea who she was talking about and struggled to make sense of the chewy Brazilian Portuguese accent. The car swerved left. Flavia Liz cried: ‘Ah, no, not this way. Ah well, we’ll see it later. Come on Robson, faster!’

This was probably a fairly typical welcome to Sao Paulo, the busiest and biggest city in the Americas by population and just about every other measure. The remoteness of my hotel was a relative thing – it can take four hours to drive across Sao Paulo, which is a constellation of four separate business districts, 39 municipalities, hundreds of neighbourhoods, and millions of miles of asphalt. More than 21 million people live in the metropolitan area.

‘Everything here is the longest, tallest, most expensive,’ said Flavia Liz. ‘Because this is where the money is!’ As our car sped through the barrios, she pointed out Japanese areas, French architecture, and a British-built railway station.

‘Sao Paulo is the real melting pot, not New York. We’re just not so good at marketing it. I have German, Italian, Dutch, French, a little Portuguese, some Moor, plus Indian and Brazilian blood.’

In this respect, she added, she was a typical Paulistana – a resident of Sao Paulo city. (A Paulista/o is someone from the surrounding state). But she was atypical in that, after travelling the world, she had made it her mission to persuade visitors that her native city is the best.

‘I want people to know it, like me,’ she said. ‘It’s not beautiful, like Rio, but it rewards anyone who puts in a little effort.’

[Travel guide: Iceland, Game of Thrones and a tour of the wild north]

As I scribbled down her positive pitch, I felt a teeny bit shameful. I’ve been using Sao Paulo’s Guarulhos airport – the busiest in South America, naturally – for more than 25 years, to travel to Argentina, where I once lived, or on to the Pantanal, Chile, Paraguay or Bolivia. I once picked up a hire-car from nearby Santos. But I’d never stopped off to see the city, accepting the disparaging views of friends, journalists and even authors of guidebooks to Brazil that the business-oriented mega-city had little to offer, what with Rio just down the road.

At last I’d come to test the received wisdom. Before anything, I wanted to get to grips with the sprawl, which Paulistas call the selva de pedra – a “jungle of stone”.

I took a lift to the roof – level 42, no less – of the Edificio Italia building downtown. For mile upon mile there were mid-rise blocks in every direction, broken only by flyovers, runways, antennae. Vultures floated over a church steeple; helicopters buzzed over the grey sea. My eye travelled, looking for architectural signatures amid the monotonous text of the supercity.

The newly published Atlas of Brutalist Architecture lists 14 structures in Sao Paulo, including a court, a church and a yacht club. The most impressive entry, however, was right there before me – the Copan building, a residential tower by Oscar Niemeyer of Brasilia fame. Built in 1953, it was, as Phaidon’s editors put it, part of a plan ‘to create a new identity’ for the city, brutalism as boldness, urban as ultimate. Its S-shape was sensual and witty, a nod to the curvy tilde in Sao Paulo.

Afterwards, Flavia Liz took me to visit some private art galleries housed in modernist buildings from the same era: Auroras, hung with the inspired works of the late Antonio Dias; the Luciana Brito, with a garden by acclaimed landscapist Roberto Burle Marx; the Vermelho, where the Tate comes shopping for new work; the lovely Lombardi photography gallery; and Apartment 61, a space devoted to the sort of furniture you need if you’re going to rent a flat in Copan.

Stroll through Avenida Paulista – the main drag and 24-hour thoroughfare, for a feel of the supercity
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All the curators were charming and welcoming, serving me coffee before showing me their spaces and/or homes. Each of them offered me a theory about their city: it was a ‘transit lounge’, a ‘city of work’, a ‘carnival-free zone’.

Sao Paulo’s status as the southern hemisphere’s art powerhouse is reflected in its public collections. The MASP modern art museum – designed by Italo-Brazilian modernist giant Lina Bo Bardi – has a world-class collection of European and Latin American art. The Pinacoteca do Estado contains an even more enticing, peerless collection of Brazilian contemporary art in a 1900 downtown building brilliantly redesigned by Pritzker-winning Paulo Mendes da Rocha in the Nineties. In Vila Madalena – one of Sao Paulo’s more bohemian quarters, awash with beautifully designed boutiques, craft ale bars, cool little cafes and small galleries and design studios – I had an eye-full of street art.

My stay coincided with the Biennial. Established in 1951, this major global art fair has its own Niemeyer building inside the huge Ibirapuera Park. I was shown round by curator Joao Correia, who used to run the Tambo gallery in London’s Regent Street.

‘I came back after 12 years in London,’ he said, ‘because I wanted to share what I had learned there, make contact with artists in the favelas and find a new way of doing art.’

He took a special interest in Pixacao, a distinctive Paulistano street art characterised by hieroglyphic-like lettering, sharp angles and bold single tones; regarded by detractors as ‘angry’ graffiti, so divisive is it that one of Sao Paulo’s past mayors sent out municipal workers armed with grey paint to cover it up.

‘Pixacao is an existential movement,’ said Joao. ‘It’s by people who feel pushed out of the city by development and gentrification. The artists, motivated by a violent, desperate need to express themselves, want to rub their existence in our faces. The mayor failed in his bid to get rid of them.’

If brain-food isn’t lacking in Sao Paulo, neither is the comestible kind. No other city in the Americas comes close for culinary ambition or, thanks to the Amazon jungle, fertile pampas and a 7,490km Atlantic coast, variety of food sources.

Helena Rizzo, of the hip but laid-back Mani restaurant, was crowned ‘world's best female chef’ in the 2014 S Pellegrino listings. Over a lunch of cashew ceviche, java plum and arrowroot gnocchi, she brushed off the laurels, returning to the melting pot theme.

‘For me, it’s the mix of things that makes our food fantastic – the immigrants brought us their cuisines. In terms of ingredients and biodiversity, we have a lot more than Peru. We have large Japanese, Levantine and Jewish communities, lots of Italians...

‘More than Rome!’ chipped in Flavia Liz.

Also, said Helena, Rio people go to bars. ‘Sao Paulo has a culture of going out to restaurants. It's how we meet.’

At Mani, at Mocoto, at Barbacoa, I ate like a Portuguese emperor. In the sumptuous five-star Palacio Tangara hotel, I slept like one. Art, food, style and fun were often conflated in a single space; Sal, a restaurant run by the presenter of Brazil's MasterChef – a Triumph-riding, heavily tattooed dude named Henrique Fogaca (who also sings in a hardcore band) – occupies the same site as the Vermelho gallery.

The impressive Copan building’s S-shape is a nod to the curvy tilde in São Paulo
Shutterstock

Sao Paulo has various natural delights too. Its parks turned out to be filled with Atlantic rainforest flora. At 2,494ft above sea level, the climate is dreamy. The city is chic, sexy, fun, wealthy and has a nightlife that puts many capitals to shame. In the districts visitors are likely to go to, Sao Paulo is also safe. So why don’t people stop over when they change planes?

Part of the reason is marketing – or lack of it. Visit Brazil, the national tourist board, prefers to use its stands to promote Rio, the Pantanal and the beaches of the north-east. Then there are hangovers from history. The Paulistas went to war with the rest of Brazil in 1932, emerging as victors in their demand for a constitutional government. The upstart state got used to being friendless, misunderstood, ignored.

The chief caveat for visitors is: get a guide. Flavia Liz was passionate as well as practical, helping me navigate and see the choicest sights, while explaining the complexities of life in the supercity. She put me right on neighbourhoods, cool people, facts and stats.

She was wrong about one thing, though. All cities, including Sao Paulo, are walkable. I spent a Sunday sauntering in Ibirapuera Park, mercifully car-free in the afternoon. I walked up and down Avenida Paulista – the main drag and 24-hour thoroughfare. In Parque Burle Marx – even the green spaces were built by modernists – I strolled in an urban forest and saw three shy monkeys and two gregarious toucans.

My five-day trip ended with a view gentler than that from the Edificio Italia, but no less sublime. The rooftop Skye Bar at Hotel Unique – shaped like a steampunk tugboat – is one of Sao Paulo’s most glamorous spots. At 9pm the pool glistened. Glasses clinked. On that Monday night it was dark out there, the lighting so muted I could almost pretend everyone wasn’t gorgeous and dressed to murder. The waiter brought me a menu and a torch.

Under a full moon, I scanned the tops of the towers and let my gaze flit across the horizon. Jets landed, choppers lifted, cars streamed out to the faraway suburbs. The sky fizzed with artificial light and the drifting emissions of a dying workday. Sao Paulo is not for everyone, but it’s a city that seems to contain every kind of person, every job, every pursuit, every problem, every other city. It’s busy, brash, big and brutal; it’s also, in its way, beautiful.