Most episodes are fascinating; the disaster is shown, and then it goes back to the beginning and shows each step toward the final outcome. The show is a combination of computer graphics, reenactments, and survivor and investigator interviews. The disasters include plane and train crashes, natural disasters, structural breakdowns, and terrorism. The episodes tend to be fairly recent disasters, going back up to about 30 years ago, but every so often they show older ones, like the Hindenburg.
This show has a good rewatchability factor, except National Geographic tends to replay many of the episodes too much and not show others. For example, the Mt. St. Helens and Columbia episodes are shown too often.