Many events can be called “the beginning.” The possibilities of controlled and uncontrolled atomic chain reactions was posited long before the first uncontrolled atomic chain reaction. See Chicago Pile and studies leading up to it.
The rock group RUSH did a great job on the concept of the bomb - not judgemental - just recognizing that it changed the world.
“Manhattan Project”
Excerpts:
...Imagine a man
Where it all began
A scientist pacing the floor
In each nation, always eager to explore
To build the best big stick
To turn the winning trick
But this was something more...
...Imagine a place
Where it all began
They gathered from across the land
To work in the secrecy of the desert sand
All of the brightest boys
To play with the biggest toys
More than they bargained for...
The big bang, took and shook the world
Shot down the rising sun
The hopeful depend on a world without end
Whatever the hopeless may say...
...The big shots, try to hold it back
Fools try to wish it away
The hopeful depend on a world without end
Whatever the hopeless may say...
I used to do a lot of work at the Hanford Nuclear site. My mom commented that a good friend of theirs worked there during the war building airplane wings. I chuckled and said “Those weren't wings he was working on!” She was adamant about it. I explained that he probably thought he was building wings as well - most of the workers weren't told what they were really working on.