Which TV show has the most-watched non-finale episode?

The summer of 1980 belonged to one question. After "Dallas" ended its third season with J.R. Ewing getting shot by an unseen assailant, "Who shot J.R.?" took over conversations from American barbecues to British pubs. T-shirts reading "Who Shot J.R.?" and "I Shot J.R." flooded the market, international bookmakers set odds on potential culprits, and a session of the Turkish parliament was suspended so legislators could get home in time to watch.

The answer was revealed in season four's fourth episode, "Who Done It," which drew roughly 83 million American viewers, and more that 350 million internationally, on November 21, 1980. The show's producers went to extreme lengths to keep the secret safe, filming multiple actors shooting J.R. The episode's success helped turn "Dallas" into America's biggest television phenomenon while popularizing the cliffhanger ending that became a staple of primetime television.