A significant part of these games takes place in a Post-Apocalyptic world. After the end of civilization as we know it, before a new and equal society has arisen to replace it. Often a world-wide nuclear war, where radiation has created mutants, entire cities are leveled, and necessities like gas, food, and water are hard to come by. However, the setting applies to any world that was destroyed following a major disaster: post-nuclear war, post-pandemic, post-zombie apocalypse, post-natural disaster (like global weather disaster or asteroid strike), or, even, post-alien invasion.