There is pretty much zero evidence of any kind in the archeological record to suggest that the world-wide flood that is depicted in the Bible actually occured.
Among the highlights: No sedimentary deposits that would indicate such massive flooding, including a total lack of the sedimentary layer that should contain fossilized remains of all plants, animals, and human civilization that would have been destroyed in the flood.
The Ark itself, a huge creation that was gently set upon a mountain top cannot be found. First, to hold two of every species, and food enough for all of them for 40 days and night would have required a MASSIVE vessel. This was before the discovery of metallurgy, so it would have required purely natural materials, and the amount of time, effort, and material that would have had to go into building the ark is insane.
Also, no trace of the ark has ever been discovered. There's some urban legends floating around about it, but nothing of any substance.
According to the story, all the animals were gathered in one place, then set free to repopulate the world. There is no evidence of such a spread from Turkey (where the ark supposedly landed) or from anywhere else, for that matter.
No scientific evidence for such a massive and widespread event = hard to believe it actually happened.