Great Flood

Parallels are often drawn between the flood waters of these myths and the primeval waters found in some creation myths since the flood waters are seen to cleanse humanity in preparation for rebirth. Most flood myths also contain a culture hero who strives to ensure this rebirth.
Origin of flood myths
Adrienne Mayor's The First Fossil Hunters and Fossil Legends of the First Americans promoted the hypothesis that flood stories were inspired by ancient observations of seashells and fish fossils inland and on mountains. The ancient Greeks, Egyptians, Romans, and Chinese all wrote about finding such remains in these locations, and the Greeks hypothesized that Earth had been covered by water several times, noting seashells and fish fossils found on mountain tops as evidence. Native Americans also expressed this belief in their early encounters with Europeans, though they had not written it down previously. However, Leonardo da Vinci postulated that an immediate deluge could not have caused the neatly ordered strata he found in the Italian Apennines.