Watch Lost Subs: Disaster at Sea (2002) : Full Movie Online Free From the National Geographic Explorer series, this documentary takes an in-depth look at four submarine accidents -- the forces that brought the machines down, the tragedy of lives lost and the heroism of the submariners who sacrificed themselves to save others. Submarines profiled are the K-19 and Kursk from the Soviet Union and the USS Thresher and Squalus