Well, it's true. At the end of the book, author Peter Brown shares about the Highline in Manhattan. After learning about this real place, Mr. Brown wondered, "What would happen if an entire city decided to truly cooperate with nature? How would that city change? How would it all begin?"
His answer is The Curious Garden, and it all started with a character named Liam.
Here's more information about the real Highline.
The first video talks about how the park was developed on the Highline railroad tracks.
Finally, the you can take a tour yourself through Google Street View.