A special expanded edition of 20/20 that chronicles 7 of the deadliest threats to humanity. It starts at number 7 (least likely), the death of stars, including the risk of gamma ray bursts and black holes. Intelligent machines and the threat of our own technology turning against us lands at number 6. Five is the inevitability of a super-volcano eruption, specifically talking about Yellowstone park. Moving on the documentary interviews scientists about the plausibility of an asteroid hit, nuclear war, plague pandemic, and ends with our foremost hazard, a process that is already taking place; climate change.
7 deadliest threats to humanity