Civil defense is how people in a city, town or country can prepare for natural disasters, civil unrest, or acts of war. It involves making sure people and buildings are safe, making sure there is enough food or supplies available, and having clear plans for what to do in an emergency. For example, people might make a plan for where to go if there is a hurricane or a wildfire, or how to stay safe if there is a riot in their town. The government will often help people prepare for civil defense by providing information and supplies, like food and first aid kits.