By Nina Nannar: ITV News Correspondent
In San Francisco's famous gay hub, the Castro, there's long been a saying, that you'll see more dogs than children there.
But times are changing and now as you walk through the area, you'll find yourself dodging pushchairs as well as pugs.
It's quite a transformation for a place that just three decades ago became famous around the world as the epicentre of a devastating killer disease, Aids.
Now the city is attempting to bring that story to an end.
The authorities are aiming to have no new infections of HIV, the virus that leads to Aids. It is a radical mission statement in a city where almost a quarter of all gay and bisexual men are HIV positive.
Part of the process, called RAPID, relies on so many things - not least all those at risk coming forward to be tested.
But the work I saw, including taking testing vans out to the streets on a Saturday night - get a test in 15 minutes on your night out - was truly impressive.
Can you really end all new HIV infections in San Francisco?
I feel even the authorities know that will be a massive challenge - but they have succeeded in one truly important thing.
And that is reminding the world that HIV and Aids are not sorted.
There may be fantastic new drugs out there which mean that you can manage an HIV infection as you would do a chronic illness, but with 35 million people in the world living with the infection, the Aids epidemic which so far has claimed 36 million people around the world, has not gone away.
Only a cure can finish it for good. A cure, that is yet to be found.
- Watch Nina Nannar's full report on ITV's On Assignment tonight at 10.40pm