Walking on flat, linear, manmade surfaces is certainly fine,
especially if I’ve got my wife or dog or a friend—or I’m exploring
a new city—but naturally deposited ground full of dips and peaks
and studded with random deformations is ideal.
And there’s growing evidence that it’s better for you, too.
(This Mark's Daily Apple article was written by Mark Sisson, and
is narrated by Tina Leaman)