Christianity isn’t the only religion that claims the flood happened. I believe some ancient religions also did (Babylonians maybe?). It bears looking into.
When you live on the banks of a large river, like many early civilizations, floods are extremely relevant.
Almost every culture on Earth includes an ancient flood story. Details vary, but the basic plot is the same: Deluge kills all but a lucky few.
* Older than Genesis is the Babylonian epic of Gilgamesh, a king who embarked on a journey to find the secret of immortality… [Gilgamesh lived about 2700 BC but the story was written about 2000 BC]
* Ancient Greeks and Romans grew up with the story of Deucalion and Pyhrra, who saved their children and a collection of animals by boarding a vessel shaped like a giant box.
* Irish legends talk about Queen Cesair and her court, who sailed for seven years to avoid drowning when the oceans overwhelmed Ireland.
* European explorers in the Americas were startled by Indian legends that sounded similar to the story of Noah. Some Spanish priests feared the devil had planted such stories in the Indians’ minds to confuse them.