November 1, 1952 — The first full test of a Hydrogen bomb is made

The bomb was code-named “Ivy Mike”. It was the first test of the Teller-Ulam bomb design, which produced yield estimated in the range of 10.4–12 Megatons (450 times as powerful as the Nagasaki bomb) when it was detonated on Elugelab Island in the Enwetak Atoll, in the Ralik chain of the Marshall Islands.

It was the first successful Hydrogen Bomb test by either side, the first fusion bomb, and the acquisition of this technology by the United States marked an escalation in the arms race of the Cold War – a little over nine months later, the Soviet Union would detonate a fusion bomb of its own.

Ivy Mike - mushroom cloud.jpg
By United States Department of Energy – This image is available from the National Nuclear Security Administration Nevada Site Office Photo Library under number IVY-52-05.
This tag does not indicate the copyright status of the attached work. A normal copyright tag is still required., Public Domain, Link

As mentioned in:

We Didn’t Start the Fire — Billy Joel

August 6, 1945 — The Bomb is dropped on Hiroshima

The Enola Gay left its base on Tinian with two companion aircraft on the morning of AUhust 6, 1945. It flew for the Japanese mainland, aiming for the city of Hiroshima. Its payload was the nuclear bomb codenamed ‘Little Boy’, which was dropped and detonated over the target at approximately 8:15 local time.

Of the 340-350 thousand people who lived in Hiroshima, about 20% were killed in the blast itself. Another 20% died of injuries sustained in the blast or its aftermath, or from radiation sickness. Still more died later of related medical issues such as a cancer. All in all, about 200,000 human lives were ended by the first use of a nuclear bomb as a weapon of war. Hiroshima itself was devastated – the few structures that survived the inital blast were damaged or destroyed in the resulting fires.

Along with the detonation of another nuclear bomb, ‘Fat Man’, over Nagasaki three days later, and similar destruction and death there, the attack on Hiroshima was the proximate cause of Japan’s surrender to the Allies, thus ending World War Two.

Another view of the mushroom cloud forming, from further away.
By Unknown – Honkawa Elementary School [1], Public Domain, Link

As mentioned in:

Mrs. O — The Dresden Dolls
Short Memory — Midnight Oil
Enola Gay — Orchestral Manoeuvres in the Dark