Photo by Pete McBride @pedromcbride // Marble Canyon, the upper stretch of the Grand Canyon, dwindles into the distance. Last week author #KevinFedarko and I walked the first 60 miles of this giant crevasse as a way to explore this hidden wilderness and the challenges it faces. To see more images from this expedition, follow @pedromcbride. Shot on assignment for @natgeo. #chasingrivers #grandcanyonnationalpark #grandcanyon #aerial #wilderness #coloradoriver by natgeo

via Instagram http://ift.tt/1MlY4vf