You know what? I had know idea that the waterfall was made out of stairs. DUH! That waterfall could be stairs that once was a temple. The tribe could be some ancient civilization.
It could have been destroyed by some one wanting more power and in trying to get it he destroyed everything and everyone other than a handful of tribe members.
Just a theory.
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You cannot do a kindness too soon, for you never know how soon it will be too late.