J. Robert Oppenheimer was the physicist that was appointed as the director of scientific research of the Manhattan Project, the American military project during the Second World War that gave birth to the world’s first nuclear bomb.

130 000 people were employed for the Manhattan Project, including many of the world’s foremost scientists and physicists. US$24 billion of today’s dollars were spent. In total, there were 3 atomic bombs detonated as a result of the Manhattan Project: 1 at the first ever test site, Jornada del Muerto (Spanish for “Route of the Dead Man”); 2 in Hiroshima and Nagasaki.

After the first and only test for the bomb, named Trinity by Oppenheimer after a poem by John Donne, he said:

We knew the world would not be the same. A few people laughed, a few people cried, most people were silent. I remembered the line from the Hindu scripture, the Bhagavad-Gita. Vishnu is trying to persuade the Prince that he should do his duty and to impress him takes on his multi-armed form and says, “Now, I am become Death, the destroyer of worlds.” I suppose we all thought that one way or another.
— J. Robert Oppenheimer

Albert Einstein, before he died expressed his regret on his act of signing the letter of recommendation to urge the then US President Franklin Roosevelt to develop an atomic bomb, told his fellow scientist Linus Pauling:

I made one great mistake in my life… when I signed the letter to President Roosevelt recommending that atom bombs be made; but there was some justification – the danger that the Germans would make them.
— Albert Einstein

Surely there are lessons to be learnt from this significant event of the human history.