Exploring old buildings is nothing new. Our word "grotesque" traces its etymological roots back to a Renaissance dig into the cave-like buried ruins of Nero's "Golden House" palace. I will never forget a nighttime 1970s exploration of an abandoned hospital in northwest Portland, Oregon. Spookissimo.
Now it's called urban exploration. Another site offers photos of abandoned buildings and vehicles.
Do abandoned buildings become "nature" in the sense of wilderness? Or are they virtual caves?