The pride of Milan - La Scala - reopened on Tuesday night with a grand performance relayed to giant screens in the city centre and even to prison inmates.
"It was really amazing. I really appreciated this opportunity to view a spectacular event like this in a big piazza," said one woman in central Milan.
Soprano Anna Kristiina Kaapola: "For me it's a dream"
At the start of the evening, the crowds laughed or whistled to see the celebrities arriving, but then, they all applauded the music.
No doubt the spirits of La Scala's past were reawakened by the choice of Tuesday night's performance.
Europa Riconosciuta ("Europe Revealed"), by Mozart's rival Antonio Salieri, was last played here when the world famous opera house first opened in 1778.
"This place is definitely haunted," chuckled Mauro Meli, La Scala's artistic director, after the dress rehearsal.
"You really feel it when you're on your own in the opera house. Maybe it's because it's on the site of a church... anyway, I hope our ghosts are pleased with what we've done."
Tuesday night's spectacle was not just about the music.
Audiences have been dying to see what kind of show La Scala could put on after three years of renovations costing 61m euros (£42m).
The backstage area and stage machinery, previously considered unsafe, have been completely ripped out, and a 38-metre high fly tower now looms above the stage, flanked by modern dressing rooms and offices.
"This is the only stage machinery in the world to move horizontally as well as vertically," explains engineer Luigi Berti.
"It's fantastic. There are one million combinations of possible movements it can do," he says, pointing at the vast engine room deep in the theatre's bowels.
This new technology now puts it in the same class as Covent Garden in London and Opera Bastille in Paris, allowing it to stage three operas in one day.
But there is a difference. At La Scala, audiences will to be able to see right inside the moving mechanisms of the stage, as well as the set changes. The aim is to create a scene within a scene.
"It's a bit like a Formula One race," explains Mr Meli. "It used to be about cars, but now you see the technicians changing tyres, inside the cockpit. This is the idea with the new La Scala - you will see everything backstage as well."
Opera not only looks very different here - it sounds better.
The horseshoe-shaped auditorium of gold and red boxes was originally built to simulate a musical instrument. But after La Scala was hit by a bomb in 1943, a concrete floor was simply laid on top of the rubble. This has now been ripped up and has been replaced by a sprung wood floor on 12 acoustic materials.
The famous spot on the stage where Maria Callas chose to sing because the acoustics were perfect no longer exists.
"The whole stage is now a Callas spot - it's very, very even," says Anna Kristiina Kaapola, a Finnish soprano sharing the leading role of Europa in the performance of Salieri's opera. "It's very easy to sing here, you don't have to force or push your voice at all, and of course for me it's a dream."
There is still some criticism that these renovations have compromised La Scala's heritage.
The architect in charge of conservation, Elizabetta Fabbri, disagrees. "Look at this beautiful mosaic floor that has been covered up for years and years," she points out.
"We've taken 11 coats of paint off these walls to reveal the original plaster. By stripping the theatre back, we've discovered its past and new links with history."
Sitting in the refurbished crimson silk boxes, it is nearly possible to imagine La Scala in the 19th Century. This was Milan's biggest social club. Each box was like a living room, where people ate, drank, played cards and incidentally listened to a bit of opera.
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In modern times, the emphasis is decidedly on the music. There is now even an electronic screen with French, English and Italian translations of the libretto tucked discreetly into each seat.
But on Tuesday a seat in one of these plush boxes for the gala performance cost up to 2,600 euros (£1,793). La Scala's first night is usually a major event, but after three years, this was the social event of the decade.
Some queued for days to get one of the 140 cheaper seats.
It is not for everyone though, said Stefania. "If you can't afford to take three days off work to queue, then you stand no chance of getting in."
"La Scala is like Gucci, Prada. It's a big brand for rich people. Everyone knows that," said Nicola.