While we probably are never going to be told the actual details of what goes on in these super-secret government projects, the official date the public is privy to is that the commencement day was today, in 1942.
The Manhattan project was a covert multi-country military research project that they claim was to research nuclear power, but me being the skeptic that I am, I believe it was the building of a bomb that was the end result all along.
It began as a joint operation between Canada and the United States and for a while the British were involved in the tag-team as well. However, internal squabbling between the powers that existed at the time resulted in the United States cutting Britain out of the deal. It had something to do with the British being over-confident in their importance in the project as they demanded total control, while paying none of the costs. It was decided in 1943 that the British would no longer receive information about the project at all. I'm not gonna get into specifics, but it is worth looking into if you are interested.
Many people erroneously believe the project was contained at one site and people who know even less believe that the project took place exclusively in Manhattan, NYC - which clearly isn't true. There was some involvement of Manhattan and NYC but the only public information I can find includes that it was simply a convenient storage area.
Other information points to Nuclear Physicist Robert Oppenheimer, who is largely contributed with being the main brain behind nuclear technology. He was a resident of the Manhattan area. As you might imagine, this project, which employed more than 130,000 people and consumed billions of dollars, was exceptionally TOP SECRET. Even today we can't get many clear-cut answers about it and I suppose it doesn't really matter.
If there is anything we know about the government, it's that we don't really know much about what goes on in the government. There's a whole lotta lies and secrets going on over there, that's for sure.
So today marks the birthday of the beginning of the most destructive power that the world has ever known. So incredibly powerful it is, i think we should consider ourselves very fortunate that it has only been used 2 times. Here's to hoping it stays that way.