Back to Sid's filmography: This film was commissioned by the National Film Board of Canada in 1974, and follows a pushing trip to the far reaches of Castleguard. Filming involved a multi-day camp over a mile from the surface supported by a team of sherpas and a cable fed from the surface to allow lighting batteries to be recharged. Caves featured in the film are Derek Ford, Tich Morris, Mike Goodchild, Charlie Brown, and Peter Thompson. It is worth noting that the Jasper National Park authorities did not allow Mike Boon's considerable contributions to the exploration of this cave to be acknowledged.