How do you floodproof a city?
It's an urgent question for hundreds of cities around the world as sea levels rise and extreme weather events become more frequent.
I'm ocean physicist Helen Cheresky and I'm in New Orleans in the deep south of the United States where the people know more than most about the dangers of floodwater.
In some of the lowest income neighbourhoods, they're taking flood defence into their own hands,
protecting their city one yard at a time.
This is Front Yard Floods for BBC World Service.
So the area we're standing in was actually one of the areas that was most affected by Hurricane Katrina.
It was under about... 10-ish feet of water.
In some places, you can still see the watermark.
My name is Megan Williams.
I am the Urban Water Program Manager for the City of New Orleans.
I was 16 when Hurricane Katrina hit in 2005.
We're watching everything on the news,
and as a 60-year-old, I'm not really comprehending what's happening.
And then we went and saw a family member's home.
They had gotten about eight feet of flooding.
I very distinctly remember driving and pulling up to their house and they had a fence around their property and there was a fish stuck in the fence.
And this is probably a six foot, five foot fence, something like that.
And it was stuck at the very top.
The mud line was at the roof inside of her home.