See, this is why he won't say the country or the building.

We know what was there before the opera house, because the whole thing is well documented:

https://rarehistoricalphotos.com/wp-content/uploads/2022/04/sydney-opera-house-construction-photos-03.webp

From here:

https://rarehistoricalphotos.com/sydney-opera-house-construction-photos/

It's a fascinating read BTW. Construction was in three phases from 1958 to 1973.

https://www.sydneyoperahouse.com/our-story/construction-begins

"Two major problems confronted the engineers in their approach to Stage One. First, the geology of Bennelong Point had not been surveyed accurately at the time of the competition guidelines. It had been assumed that the promontory comprised Hawkesbury sandstone mass, like the surrounding land; whereas in fact, it was made of loose alluvial deposits permeated with seawater and completely unsuitable for bearing the weight of the intended structure.

Some 700 steel-cased concrete shafts, nearly 1 metre each in diameter, were bored down into the perimeter and northern half of the site. Mass concrete foundations filled in the unstable rock in the central area of the site. This preparatory work had not been budgeted for, setting the building on a course of extended overruns beyond its estimated cost of 3.5 million pounds.

The second major problem related to the as yet unknown weight of the roof, which would change dramatically in the coming years. The anchor points of the roof were at this stage only vaguely discernible; the load they would have to bear was unknown."

😳