Is There a Flood Story?

There's so much monalities between culture. Why is it that every culture has a story about a flood? I don't think the israelites made i to north america during the exodus. And maybe these are just ghosts from a previous conflict, but it's weird that they have patches and insignia from the military that are either legit but not in current use, or little bit off. Almost reminds me of the men in black stories where the people show up to investigate an experience, and then they're just off. It's really strange stuff like their mimicking human behavior.