Antimatter Bomb

The antimatter bomb was the single most destructive weapon in human history. Created by the USSDF, its explosive capacity was equal to that of the meteor that wiped out the dinosaurs. It was codenamed Galaxy.

Cold War
Following the test of the Tsar Bomba by the Soviet Union during the Cold War, the United States realized that to ever become the sole superpower of Earth, they would need a weapon so powerful it could literally obliterate the planet. The USSDF, under John F. Kennedy, began experimenting with antimatter--technology they had obtained from the Nazis' secret weapon, Die Glocke, after World War II. By 1970, they had created the first prototype antimatter bomb. In 1991, after the Soviet Union's collapse, the antimatter bomb was disabled and transported to a secret base in Albuquerque, New Mexico, for storage.

President Dawson
Shortly following his election to the presidency of the United States, Kevin Dawson called for bomb to taken out of storage, as recent relations with foreign countries had been strained under former president Donald Trump. This was known as the "Christmas Initiative," as the bomb was transported to Site (REDACTED) on Christmas Day.

Operation Talisman and the Rain of Fire
After the formation of Operation Talisman, the antimatter bomb was put on standby and the launch codes were delivered to President Dawson for usage at any time. On Independence Day 2030, the Augments detonated a dirty bomb in Washington DC, having obtained the materials from their crusade through Russia.Dawson was notified of the imminent blast and was evacuated to Site (REDACTED), where a secure communications line was set up between him, Vladimir Putin, Xi Jinping, and Isaac McCall to discuss the imminent Augment victory. Dawson notified the other three leaders about the antimatter bomb, and after a long discussion, a 3/4 vote (Putin opposed) led Dawson to order the USSDF to drop the bomb over Khar-Us, Mongolia.

Aftermath
Due to the sheer power contained in just a gram of antimatter, the Galaxy bomb possessed an explosive capacity of 21 billion Hiroshima bombs.

A cloud of super-heated dust, ash and steam spread from the ground zero less than a second after impact. Excavated material along ejected out of the atmosphere by the blast was heated to incandescence upon re-entry, igniting wildfires, and the ground seemed to liquify as it became superheated and rippled for hundreds of miles. Colossal shockwaves from the explosion caused earthquakes and volcanic eruptions to ensue. The detonation site was reduced to a 64 x 19 mile crater, where rock literally boiled. The antimatter properties of the Galaxy bomb meant that unlike conventional nuclear weapons of the time, it did not produce radioactive fallout. However, the amount of debris that was blasted into the air proved to be just as detrimental. The emission of dust and particles covered the entire surface of the Earth for several years, possibly a decade, creating a harsh environment for living things.

Some areas of the world were unaffected, such as Australia and Scandinavia, however, others were hit especially hard. Pakistan, Africa and South America took the worst damage as trade winds carried much of the debris to the southwest.