Watch Diving into the Unknown

Four Finnish cave divers face their worst nightmare when two of their friends drown deep inside an underwater cave in Norway. When the official recovery operation is called off by the Norwegian and British authorities after being deemed too risky, the friends set out on a secret mission to retrieve the bodies themselves.

Diving into the Unknown is a 2017 documentary with a runtime of 1 hour and 22 minutes. It has received mostly positive reviews from critics and viewers, who have given it an IMDb score of 7.0.