Today, January 26, is Australia Day. But today in Sydney I saw two Australias marking the occasion.

At the top end of town, around Circular Quay, The Rocks, the Botanic Gardens, Hyde Park, tens of thousands of people watched the ferrythons and the surf-ski races on the harbour, waiting for the display of the tall ships. Or they ate "typical" Aussie tucker, watched outdoor concerts by the likes of the Hooley Dooleys, the Audreys or [insert forgettable Australian Idol alumnus here]. Or they thronged Macquarie Street to see the display of hundreds of vintage cars (inasmuch as a 1967 Cortina or the Holden Monaro can be deemed vintage).

And they waved their Australian flags - you know, the one that could almost but not quite pass for its New Zealand counterpart - by the squillion. They brought them with them from home, or picked them up at the info kiosks, or, as in my case, have one thrust into my hand by a promotions girl representing next weekend's A1 Grand Prix at Eastern Creek. Her flag even had an ad for the car race where the reverse of the ensign would normally be. (Hello, protocol?)

Lots of people in the city this morning. Lots of Aussie flag tattoos painted onto white Aussie faces, arms, shoulders, you name it.

I wonder how many knew what they were commemorating? Arthur Phillip... isn't that Prince Charles' middle name?

The other Australia Day - which I visited this afternoon - knew. To the indigenous Australians, whose forebears have been on this continent for forty thousand years or more, January 26, 1788 was the day the aliens landed. Took their land, spread their disease, raped, pillaged, murdered, and did their darndest to wipe out a society that they didn't even try to understand.

It has been known as "Invasion Day" or "Day of Mourning", but more recently the term "Survival Day", for "Survival Day of our Indigenous Heritage", has taken root among the aboriginal nations of Australia. Today, in Sydney they held their fifth annual January 26 concert. "Yabun 2007", named for the Eora word for "Song with a beat", was held at Victoria Park, Broadway, at the bottom end of town, and there were a few thousand people there, enjoying the sun, the music played by indigenous performers, and enjoying each other's company. No crushing, impersonal throngs such as those around the harbour.

And no silly flag-waving either. Two flags flew from either side of the main stage - one, the aboriginal flag, the other, that of the Torres Strait islanders. No Union Jack-infested fabric anywhere in sight. And no mega-rich media sponsor to bankroll flags for everyone. No, here they respect their flag, but more importantly they respect each other.

There was something that really got to me today which brings home the comparison between these two Australias. At the Quay, I bumped into that well-dressed lady with the A1 Grand Prix paraphenalia. Then, at the American Express Marquee (with the big TV screen tuned into the tennis) on the Opera House forecourts, the chap at the information kiosk started giving me the hard sell to sign up for the sponsor's card, when all I wanted was a brochure with a map inside.

No one in your face at Yabun, but instead of "prestige" credit cards and high-tech car races, the stalls were promoting safe sex, diabetes prevention, TAFE courses and enrolment for the next election.

These people have been the custodians of our land since time immemorial. We've let them down badly these past 219 years.

I have no problem with celebrating Australia's national day on January 26. It's a date that more or less brings down the curtain on the summer holidays and is a chance for families to celebrate our nation together. But let's remember that this day marks the occasion when we immigrants brought the best of our culture and knowhow, and the worst of our greed and inhumanity, to these shores. And remember that we should be making things right.