Last of the Great Unknown
The story of Grand Canyon's hidden slot canyons, the canyoneers who systematically explored their drainages, and the secrets hidden deep within their walls.
- Tür: Belgesel
- Stüdyo:
- Anahtar kelime: sports, grand canyon
- Oyuncular: Bill Formanek, Todd Martin, Dave Nally, Rich Rudow, Guy Smith
