However, this is not the full answer. Archaeologists found destruction layers between the Bronze and Iron Age layers. This means that there was some catastrophe that happened to usher in the Iron Age. There was a significant change in culture as well. Natural disasters such as floods and earthquakes have been suggested, but this is probably not the case. Civil unrest or invasion from outside is more likely, and the reason that the invaders succeeded was most likely due to their superior weapons and superior tactics. They were able to conquer civilizations that relied on chariots because no one had succeeded in developing a way to stop these war machines. The invaders did, and eventually the chariot went out of style. People began relying more on footsoldiers to go to war. This is the essence of the change between the Bronze Age and the Iron Age.