Right turn on red.
Nm
Sure it was. The first written sentance was “Dear Diary, today I invented writing. I wish that I could write down the location, date and time for posterity but I have not yet invented the map, sundial or calendar”.
The further back in time, the more important. The A-bomb just isn’t that big a deal in the scheme of things. Yet.
Invention of writing is up there, but like was mentioned before, the actual invention (probably more like a slow, gradual development) wasn’t recorded.
I’d say the next best thing is the philosophical awakening that happened in China, India, the Middle East, and Greece all around the same time, 500 BC. Confucius, Socrates, Buddha, not to mention the development of abstract mathematics, modern political theories like democracy, etc.
Don’t know if that counts as “an event” though.
Sharknado, then Thriller, then Sliced Bread.
The Internet. Nothing has changed daily life quicker and more thoroughly. And history will prove me right.
How about the invention of either paper, gunpowder, or microchips?
It would have to be something that’s significant to all peoples of Earth, not just the ones consigned to a particular faith or national borders.
[ul]
[li]Reaching Outer Space: It showed us capable of leaving the planet, but the moon landing proved to be a more lasting memory.[/li]
[li]Invention of the Computer: Would that mean the first abacus, or the first attempt to measure mathematical functions with tools, or the first machine capable of such with minimal human interaction? It wasn’t a sudden event. It was the result of industrial evolution.[/li]
[li]Invention of the train: It enabled mass transit without use of beasts of burden, which led to innovations in manufacturing, warfare, banking, delivery of goods and resources, the list goes on. Eventually eclipsed by invention of the automobile, in turn eclipsed by invention of the plane, etc.[/li]
[li]Invention of weapons more advanced than clubs: axes, knives, swords, pikes, arrows, crossbows, siege weapons, guns, cannons, bombs, tanks, drones… each of these advances in weaponry enabled the winning of wars, the dominance of one culture over another, dictation of international policy, economics, and so on.[/li]
[li]Invention of medical techniques: Once we got past leeches and humors, we started using vaccination, pills, prosthetics, artificial organs, pacemakers, etc to extend life and overcome disease.[/li][/ul]
The Civilization game has players choosing between pottery, the wheel and the alphabet to begin their new civilization. These each predate recorded history to some degree, unless you consider cave drawings. So, maybe the invention of the first sharp thing that could scratch rock and leave enduring imagery would be considered mankind’s most significant event.
Normally I would say something like “Check the order here”.
But I see you’re going for a subtle tribute to the OP’s username, from whom we have not heard since his OP. Which consisted of the thread title alone, pretty much.
So I agree with what you’re doing here. Kudos.
Gutenberg’s printing press.
Right after they sang the line “I know I will be leaving here.”
Or maybe the alleged Birth of Jesus.
Maybe amend that to be The invention of the printing press and I’ll cast my vote there.
The impact of the meteor that killed the dinosaurs. It was recorded - I read about it.
It sort of left a mark as well, so “recorded” counts that way as well. It just wasn’t video taped.
Trans-oceanic navigation. All the other things, like writing, occurred independently at many different places at different times, and would have evolved in the natural order of inquisitiveness. Sailing across oceans was a huge and daring leap.
Covered this in post #17. Real or fictional his birth was recorded and the story was told. Still impacting many peoples lives today in countless ways, even people who don’t believe in him. How many other fictional or real characters have had such an impact on peoples lives (or deaths to non-believers? 
)
Columbus’ voyage to America. It had a huge impact on history that was both immediate and enduring. And it was not an obvious development of past history - it’s easy to imagine it not occurring.
Two I haven’t seen mentioned:
- Charlemagne crowned HRE (It was neither Holy, nor Roman, nor an Empire)
- Battle of Hastings
Both set important political events in motion
My first thought was: Birth of Christ, surprised such an atheistic group mentioned it. Constantine converting also a great pick.
But without Jesus, civilization would have evolved in very much the same way, centered on some other charismatic claimant to unseen powers. It’s like saying Elvis was important to music, because he had charisma, a loud band ( = disciples), and a good promoter ( = the Pope). If not him, somebody else.
Or the diary.
You could quibble about the “recorded history” part (and perhaps more so about it being a single “event”), but I would go with the creation of the first alphabetic and numbering systems.
They allowed not only for compact and abstract representation of both things and ideas, but also a way of preserving them across time and distance that doesn’t rely on personal memory and exclusively oral communication.
No other living creature on the planet has anything that begins to approach this. Nothing else you can name (even language itself, which many creatures have at least some primitive version of) distinguishes humans so thoroughly from other species.