France still has WWI unexploded ordnance, and keep-out areas are still being de-mined. This has been going on for a century now. About 900 tons of explosives are removed each year. Completion in 700 years at the current rate.[1]

[1] https://www.warhistoryonline.com/world-war-i/the-red-zone-la...

Does Australia have any landmines? I was under the impression that we had some areas with sea mines which had been swept but still weren't guaranteed safe, and that was it.

There are an estimated one to two million mines in the Korean DMZ. Emplaced by both the South and North Koreans since the 1950s. There is no possibility all those mines are mapped properly. And most of them are not the self-disabling/destroying kind. It will take generations to clear.

Is that actual land mines or generic lost explosives and unexploded bombs?

Cause the latter is pretty common in Europe too, but I'm surprised you have actually minefields which haven't been cleared up in Australia.

I imagine a lot has to do with motivation. Canada has UXO that it doesn't clean up as land is abundant.

This feels like a perfect use case for AI.