victor vescovo: the other members that were on board were p.h. nargeole. he was involved in virtually every major expedition to titanic. and then hamish harding was a passenger on the vessel. titanic was something that he just really, really wanted to see. and he thought-- in his own words to me, he thought that the titan was safe enough. [tense music] oren liebermann: oceangate explorations would give you a few hours on the bottom of the ocean with the titanic on board their sub, the titan. but 1 hour 45 minutes into the dive, communication with the titan was lost. there was 96 hours of oxygen on board the titan, so the timeline is ticking from the very beginning. there was hope that they were possibly still alive. it was truly a mystery playing out in real time. and we all wondered, did the five people on board the titan lose their lives on the very wreck they were trying to explore? [horn blaring] parks stephenson: i've heard it said once that the three most recognized words in the english language are “god,” “coca-cola,” and “titanic.” what is it about

victor vescovo: only a very few number of people have actually been to titanic, less than 50. [dramatic music] you had a lot of mystery about why it went down so quickly, who survived, and who didn't. it's a fascinating story, but people should not risk their lives to see this wreck at 4,000 meters. that is not a normal thing to do. [suspenseful music] it simply is adding to the intrigue of the titanic that 100 years later, it's still leading people to their death. [dramatic music]