As for Lost Speedways, Earnhardt says the discovery of the Titanic was what truly inspired his curiosity for exploring lost and forgotten historical sites.
“It kickstarted this real obsession or passion for me of abandoned things. Sunken ships: I want to know the story of that ship. I want to know the story of that amusement park or whatever it is that’s been abandoned or been left,” he explained. “That spilled over into my world of racing and motorsports. About a decade ago I started to, just as a hobby I guess, pin locations on a map on my computer of abandoned race tracks.”
source: eonline.com