Hosted by Robert Stack from 1987 to 2002, Unsolved Mysteries was a popular long-running series that examined cold cases ranging from bizarre crimes and missing persons to paranormal activity and conspiracy theories through interviews and re-enactments. Viewers were asked to call in with any new information they had and their contributions led to breakthroughs in multiple cases. Many of the original episodes have now been updated with crucial new information for the series' digital release.