In 1942, the United States began a secret research and development effort with the Army designation

Manhattan Project, and its larger holistic designation, which included that army component

of the program, among others, the development of substitute materials, was more or less set

aside as the term Manhattan Project became popular with those in the know.

So there was, technically, a different name for the whole of this R&D project,

but that smaller component of it ultimately came to lend its name to the whole thing.

At its height, that larger effort that became known as the

Manhattan Project employed more than 130,000 people, cost about $2 billion at the time, which is about

$23 billion in modern dollars, and about 90% of that funding was spent on factories and the costs associated

with producing fissile materials, radioactive components capable of sustaining a nuclear reaction.

The other 10% was spent actually developing and building the ostensible purpose of the program,

nuclear weapons, the first of which, in terms of those fully built and used at least,

were called Fat Man and Little Boy, which represented two different approaches to triggering

and sustaining a weaponized version of this type of reaction.

These bombs, famously or infamously, were dropped on the cities of Hiroshima and Nagasaki in

Japan, near the end of World War II, at the beginning of August 1945, and the debate still

rages as to whether dropping them was more about ending

the war sooner rather than later, and thus preventing more casualties that might have otherwise

been inflicted on both the American and Japanese sides, if a full-on invasion of Japan

had become necessary, or if it was more about demonstrating that

these weapons had become available to the U.S. military, serving as a great big flashing sign that

everybody else better watch out. There's a good chance that both purposes played into the

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