I have to say this is the first picture that I've ever really questioned posting. . .
This was taken somewhere along the upper part of the Bright Angel trail in the Grand Canyon. I waited for a fair while before I got the person into the composition I wanted on the trail - but something still seemed lacking in color.
After desaturating and increasing the contrast it just seems to bring the photo down to the key elements - the size of man in nature.
Maybe you can't even see the person - but look for a little bit and you'll find him.