Dallas: Who Shot JR. - Can someone explain this

[pegusus]

ok so i'm watching the emmy's (i know i'm gay) and they mention how this show still holds the record for like biggest viewership when this episode came on. I've heard about this a few times but I've never seen one episode of this show and don't really know anything about it. I know it's before my time but there are other shows before my time that I've seen or heard about more so I'm just wondering to anyone who was around then what was the gist of this show or the big deal about it that even like 30 years later it still holds the record for most viewership. I find that absolutely insane that this show could hold this record this long esp. granted there are more tvs nowadays and idk i guess people watch more tv.