How the World’s Largest Garbage Dump Evolved Into a Green Oasis: https://www.nytimes.com/2020/08/14/nyregion/freshkills-garbage-dump-nyc.html
The radical fix for a noxious landfill in Staten Island: Bury the trash, plant some grass and do nothing for 20 years.
(Freshkills didn't start as an ecological "undo human harm" project, but that doesn't mean it couldn't be turned into one.)