Disaster / Destruction
In a dying Earth with limited natural resources left and pandemic running rampant, the nations lashed out at each other. This sparked a fire that would not go out until the world as it was known was destroyed.
Political unrest and a scramble for the Earth's remaining resources eventually culminated in the greatest war known to man. It began with cyberwarfare, then it escalated to fighting between soldiers on the ground, in the ocean, and in the air. Eventually the world's nations turned to biological and chemical warfare. When all else failed and they felt like they had nothing left to lose, everyone launched their nuclear armaments at each other. Some portions of humanity were hidden away in underground bunkers to await the world's return to habitability, other small remnants eked out what living they could in small, relatively unaffected colonies as they rode out the ensuing nuclear winter. However no one could disagree that, when the bombs fell, the world went silent.