They call it, affectionately, "the Nuns' Scrum" - and, yes, there is a touch of the wimples about its emblematic cluster of shell-like structures. But since it was opened in 1973, the Sydney Opera House has become an icon of Australia and of architecture in the 20th century.
Images of this extraordinary building are so familiar that nearly everyone in the world would recognise it instantly. Yet Jrn Utzon, its Danish architect, had nothing to do with completing the building and has never returned to Sydney to see his most famous creation.
My great fear walking along the east side of Circular Quay towards Bennelong Point, before the Opera House loomed into view, was that I might be disappointed. But it looked just as dramatic as you would expect, rising from a vast podium of reconstituted stone.
The million ceramic tiles used to clad its concrete shells glint in the sunlight, making it all the more dazzling. The cream-coloured tiles are arranged in a pattern that resembles the stitching on a sail, in a very obvious reference to its pre-eminent position in Sydney Harbour.
There were people everywhere, many in queues for the guided tours that take place every hour other than during performances. You learn that it has no fewer than five auditoriums: a 2,500seat concert hall, a 1,500-seat opera theatre and three smaller performance spaces.
It was over a controversial decision by the New South Wales state government to downgrade the opera element in favour of the concert hall that Jrn Utzon resigned his commission in 1965, despite having worked on the gargantuan cultural project for nearly a decade.
He had won the 1957 international competition, which attracted more than 200 entrants from all over the world, mainly because Eero Saarinen, the influential Finnish-American architect and member of the jury, rescued his intriguing free-hand sketches from the bin.
Utzon spent the next two years fleshing out his scheme in collaboration with structural engineers Ove Arup and Partners. But because it took another few years to figure out how the huge concrete shells could be built, only the construction of the podium could start in 1959.
The Danish architect, then in his late 30s, cracked the structural problem by devising a system for building the shells. A complex series of disparate but interlocking pieces were to be cast on-site and then slotted into place in much the same way as a jigsaw puzzle.
After Utzon resigned in a fit of pique, vowing never to return, the job of making the Sydney Opera House stand up fell to Dundalk-born Peter Rice, then a young structural engineer with Ove Arup, whose untimely death in 1993 robbed the construction world of one of its most brilliant talents.
Architectural purists are not alone in finding the interiors of the opera house somewhat disappointing. And yes, they do seem ordinary, even sedate, compared to the structural drama of its exterior. But there are now plans to remodel the interiors along the lines Utzon intended.
The erection of three new apartment buildings over a ground-floor shopping arcade on the east side of Circular Quay provoked some controversy, with many arguing that once the office blocks that stood on the site were demolished, the open aspect should have been kept.
In truth, the crisply-designed nine- to 12-storey buildings, with their green-tinted glazing and stainless steel balcony rails, are not only an adornment to Circular Quay, but they also allow the opera house to reveal itself quite spectacularly. Plus, everyone knows it's there anyway. Way back in 1957, it was estimated that Utzon's "grand project" would cost A$7 million (£3.4 million) to construct. By the time it was finished 16 years later, the figure had soared to A$120 million (£58.2 million) and the Australians had come up with the idea of a national lottery to pay for it.
Everyone seems to have bought a ticket, and so much money was raised that the opera house was debt-free on the day it opened - a remarkable achievement. Asked by someone on the tour who its owner was, our guide replied without hesitation: "The people of Australia."
Take a bow, all you Aussies out there. We owe you one.