I thought I could place it myself, I was going to be an Internet about it and drop a fence right in the middle of this roundabout with like ten buses going around it, but I'm stuck on this "finding a place in the world," so I don't really get the purpose of this app at all.
I have no way to distinguish if I actually am affecting this "world." For all I know someone is just modeling stuff, and when I draw a "fence" it goes and finds a random fence and says "here's the fence you made, yay for you!"
I have a feeling that's exactly what's going on here because I drew a small bush and it said "Thank you, the world needed 4 of those!".
Also take a look at where most of the trees were created at. Shoreline Amphitheatre. :)