On August 6, 1945, the United States dropped an atomic bomb on the Japanese city of Hiroshima, killing tens of thousands of people. The bombing was a key event in the ultimately successful effort to end World War II. But it also ushered in the nuclear age, and the threat of nuclear war has hung over the world ever since.

In the years leading up to the Hiroshima bombing, there were a number of opportunities to prevent it. If any of those opportunities had been seized, the world might be a very different place today.

The first opportunity to prevent the Hiroshima bombing came in the 1930s, when the United States had the chance to stop the development of nuclear weapons. Instead, the US government encouraged the development of nuclear weapons, both through its own research and through its support of research in other countries.

If the US had chosen to prevent the development of nuclear weapons, it could have done so in a number of ways. It could have stopped its own research, or it could have negotiated international agreements to limit or prohibit the development of nuclear weapons.

Instead, the US government decided to develop nuclear weapons, and the first atomic bombs were built in the early 1940s. At that point, there was still a chance to prevent the use of nuclear weapons. But instead of working to prevent their use, the US government began making plans to use them.

Those plans came to fruition on August 6, 1945, when the US dropped an atomic bomb on the Japanese city of Hiroshima. The bombing killed tens of thousands of people, and it was a key event in the ultimately successful effort to end World War II. But it also ushered in the nuclear age, and the threat of nuclear war has hung over the world ever since.

If the US had chosen to prevent the development of nuclear weapons, or if it had chosen to prevent their use, the world would be a very different place today. But those opportunities were missed, and the world has been living with the consequences ever since.