Last of the Great Unknown
IMDB: 7.1 22m
Overview: The story of Grand Canyon's hidden slot canyons, the canyoneers who systematically explored their drainages, and the secrets hidden deep within their walls.
Released: 2012
Duration: 22m
Genre: Documentary
Country: United States of America
Cast: Bill Formanek, Todd Martin, Dave Nally, Rich Rudow, Guy Smith
Director: Dan Ransom
