These plaques were to be found all along the trail and throughout the park.  Also, those are the shoes that kept my feet in excellent shape throughout my days of strenuous hiking.  While others were taking off their shoes and massaging their feet, putting on moleskin, finding a place to sit whenever possible, or just complaining; Gramma Barbie was smiling!!!  The only day I had ANY difficulty with my feet was the half day when I wore my boots!