I think we all know what the most memorable event was…but if someone asked you that question on 9/10/01, which would you choose? (I deliberately excluded anything before 1970 to eliminate such obvious choices as the moon landing or the JFK assassination…plus, I wasn’t alive that far back. 
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My choice would be either the Challenger disaster or the OK City bombing. Anyone else?
From afar, it’s hard to judge the impact of world events, but the only other time I can recall every single one of our TV networks suspending all their programming and going to 24 hour live feeds was when DPOW was killed in Paris - they all had live, uninterrupted coverage of her funeral too.
While it didn’t attract around the clock programming, the Berlin wall coming down would have to rank as pretty significant, and memorable for positive reasons.
The ability to provide almost instant, live visual coverage of major events must inevitable influence the extent to which those events imprint themselves on us. The events of 11 September would have left an imprint because of their sheer magnitude, even if we didn’t live in a CNN world, I’m not sure that’s true of many other “memorable” events.
I would have to pick the Challenger explosion.
The first really important thing I remember is the Iranian hostage crisis and their subsequent release. I would pick this simply because it had a significant impact on America’s “standing” [sub]I think I’m looking for another word here, but that’s close enough[/sub] in the Middle East.
This depends on perspective and timescale.
In the context of the OP, it’s difficult to disassociate memorable from catastrophic so presumably we are looking for something of this nature.
I think you would have to search very hard to find something more memorable that the genocide perpetrated by the Hutus against the Tutsis in Rwanda between April and July, 1994.
800,000 people were killed in 100 days.
In order to refresh my memory, as if I needed to, I dropped Rwanda followed by genocide into Google. The whole story is there on the first item.
These vicious killings drew plenty of interest in the Western media, but many people just shrugged their shoulders and carried on eating their breakfast.
About what you would expect really.
Well, I’d have to go with Nixon’s resignation as the second most memorable event. That would put it behind the end of the Viet Nam War which was the most memorable event of the last thirty years.
I only say that because our proximity in time to the WTC (not even two weeks yet) hardly makes it memorable. It is all too much with us, on our minds all of the time.
We don’t know where this current trend is leading us. Perhaps 9/11/01 will be swamped in a flood of other dates of equally horrific attacks. Then again, perhaps it will mark the watershed from which international terrorism will have abated from the world scene. I don’t know.
But I do know that it is too early for me to place this most recent attack in any cogent ranking of recent history.
The Rwanda link is here.
For me it has to be the Oklahoma City bombing because it affected me personally and will forever be tied in my mind with the death of a friend’s child who died two days after the bombing while I was in OKC handing out coffee, hugs and a shoulder to cry on for the rescue crews.
But Challenger is tied with that for me because of my lifelong love of the space program (I remember watching the broadcasts of the lunar landing when I was 7). I was so afraid that they would ground the program indefinately out of fear. When they finally launched another shuttle, I watched it with tears in my eyes.
I’ll have to agree with blur and Arden Ranger about the Challenger and OKC Bombings.
You can also throw in Waco, NYC WTC Bombing 1, and Lennon’s assassination to the list.
and I’d have to rank Rwanda at or near the top.
Other candidates (some already mentioned, some not):
the Cambodian killing fields
the fall of the Berlin Wall
Nixon’s resignation
the fall of Vietnam
Sadat’s visit to Jerusalem, 1977
the Iran hostage crisis
Jim Jones cult suicide
the OKC bombing
in more or less that order for me.
I figured that it was time for a geezer to drop in and recall some of the ‘big ones’ from the 1970s.
Looking over a lot of the suggestions here, it would appear that “memorable” = “dramatic footage”. Not that it’s a bad thing.
Personally, I believe the Wall coming down (and the implications: fall of communism etc.) has to take the prize. 50 years of established world order, assumed to continue more or less indefinitely, crumbling away like the fragments of a bad dream.
S. Norman
Man, you folks are blood-thirsty people 
As far as an event that will be remembered in history, I also vote for the fall of the Berlin wall. I think it was a huge step towards reshaping the western world as it is today.
My vote goes for Nixon’s resignation - one of the few “events” during the time period where I can clearly remember where I was at the time I heard. (Of course, by that standard, Reagan getting shot would be right up there. We were pissed because the coverage pre-empted Luke and Laura’s wedding!)
Re: Rwanda, there’s a huge story on it and the US’s role (or nonrole) in last month’s Atlantic. (Not to mention some absolutely stomach-turning photos.)
My friends and I were trying to figure this out several hours after the WTC bombing. We basically came up with: the Challenger and the fall of The Wall. You always get that question, “Where were you when the Challenger exploded?” I haven’t heard this question repeated as often about any other event. I don’t remember where I was when the OK bombing happened, the Wall was a more protracted event, and Waco just wasn’t as memorable for me as the rest. I can certainly see the WTC bombing being used decades from now in the same context. So for an American, at least one born in the mid-70s, I would certainly say that the Challenger disaster ranks as the most memorable single event in the last 30 years.
As for Rwanda, I would certainly consider it memorable, some of the most memorable photographs (particularly one of the profile of a macheted Tutsi [alive, in a refugee camp]by James Nachtwey) for me come from that period. Unfortunately, though, I don’t think most Americans would even list this in their top 10 memorable events of the 90s, much less the last 30 years. But then, it just becomes a question of what we define “memorable” as.
I think of “memorable” as things that come to mind readily, rather than things that affected the greatest number of people, or tied up the media.
In addition to most of the above…
Desert Storm.
Breakup of the Soviet Union.
Chernobyl.
AIDS.
And so there’s really no right or wrong definition.
Speaking for myself, long-term memorability will depend on how important an event was in and of itself, and how it either drove or captured its times.
That helps me knock off things like Diana’s death, Lennon’s assassination, and the Challenger disaster from my personal list: none were all that fundamentally significant, and none really made much of a long-term difference in anything.
But that’s by my particular standards of memorability; YMMV.
Back to the list: I shoulda remembered Chernobyl.
And I kinda consider the fall of the Soviet Union to be more or less the continuation of what began in the other Warsaw Pact (dusting off that phrase) countries in the fall of 1989.
Wow, I can’t believe no one has mentioned the O.J. verdict. That long, protracted televised trial was watched by a lot of people, but I seem to remember the actual day of the verdict in particular was a big one that loads of people watched and remembered.
All the events you have all mentioned are far more important than the one I will mention, but he event that is most memorable to me (as in, I remember exactly where and when I was when I heard) was the murder of John Lennon. I can’t say for sure why I feel so strongly about this event.
Definetly Challenger for me. I was 13 at the time…old enough to know what it really meant. It was the only thing that comes to mind that I can remember exactly where I was, what I was doing and who said what to me to let me know what happened.
Well, it’s certainly true that good footage equals memorable these days.
Let me throw this one out:
Tianenmen Square.
Those kids assembling. I and my college pals (I was a senior) were wondering if China was going to follow the east bloc on the path to freedom.
Then the tanks rolled in.