Evacuation is a term that comes from Latin language. Literally, it means "emptying". Most of the time it means that people leave an area or a zone because of an imminent danger or threat. Evacuations are planned, and people should leave the zone of danger according to the plan. The causes for evacuations can be natural disasters such as flooding or volcano eruptions, or they can be man-made ones, like a bomb in a building, a fire on a train in a tunnel or an industrial accident.