If you like real-world natural mysteries, you may have heard of this:
https://www.wthr.com/article/only-in-indiana-stoned
http://www.abovetopsecret.com/forum/thread28037/pg1
http://dailyabuse.typepad.com/odd_midwe ... in_tr.html
For years nobody could explain how these rocks got into high tree branches way up in trees in Yellowwood State Forest.
I met the author of Single Harness (http://www.amazon.com/Single-Harness-Ne ... 149690009X), and the book finally revealed the mystery. I highly recommend the book if like reading about military hero's, especially the quiet kind.
Here's a review https://www.kirkusreviews.com/book-revi ... e-harness/