When Spanish missionaries began evangelizing the Incans of Peru, they discovered their civilization had not forgotten the great flood that had destroyed early humanity. Indeed, virtually all cultures bear such a memory, and the stories usually follow the same pattern. Earth is full of sin, God punishes mankind through a flood, but saves those on a boat. Each culture pointed to the highest mountain in their region, and said that is where the boat landed. Interestingly, a few cultures record humans surviving by climbing to the tops of these mountains. Either way, we have a widespread and independent memory of a distant event. Some venture to say that this is the result of local flooding these various cultures experienced, and then it was enlarged into the mythical flood that we now believe to have happened. However the similarities and agreement on the timing of this event don't fit that hypothesis.
The two main thoughts on the flood in our day are that it either was literal, and occurred some 4,000 years ago, or that it's closer to a metaphor, a parable if you will. Since our Lord spoke of Noah as if he was a real figure, and the long standing tradition of the Church is to take these Genesis events as historical in some sense; I am inclined to not believe the flood was a mere metaphor. But at the same time, I don't agree with the young earth creationist world view.
So what is another, perhaps more likely view? First some recent discoveries that help establish a global and catastrophic event occurring.
A couple years ago I read an article about scientists discovering a bottleneck in human history. A drop in genetic diversity some 50,000 to 70,000 years ago suggested that the human population was a low as 2,000 people. The exact cause of the bottleneck is unknown, speculations are that it's linked to climate changes caused by the super volcano Toba's explosion in Indonesia. Keep this volcanic explosion in mind as we go one. Whatever the cause, there is evidence to suggest that humanity was significantly reduced by some unknown calamity, this is point one.
Secondly, by further studying genetics, scientists have been able to link all males to one male living some 50,000 years ago. All males bear a Y-chromosome that stems back to this one male, and scientists have named him genetic Adam. Any reader of the Bible will know that a more appropriate title would be genetic Noah, since eight people are recorded to have survived the flood, and three of them were the sons of Noah. Therefore, there is a genetic link between all human males to this one male, living in the time of the bottle neck mentioned above.
Thirdly, these events roughly coincide with another significant event in human history, the crossing of the African land bridge. According to the out of Africa theory, humans were confined to the African continent, until some 50,000 years ago they crossed the land bridge to colonize other parts of the world. Again, returning to the Bible we see that it was Noah's sons who spread to the other parts of the world, Japheth who colonized Europe, Ham who colonized Africa, and Shem the Middle East and Asia.
All these facts form a pattern that fits nicely with the Genesis account, but who is to believe that these events really took place 50,000+ years ago? I read the Old Catholic Encyclopedia, and to my surprise there are some things that can warrant this consideration. For one, the genealogies in the Old Testament need not be comprehensive. In other words, when the Bible says Person X was son of Person Y, "son" may really mean descendent, and that therefore there may be numerous links in-between the two. This fact alone renders the dating based for a young earth as untenable. Furthermore, Genesis never explicitly indicates that the whole earth was flooded; rather the "land" was flooded. This opens the possibility that the flood was global anthropologically, but not geographically. If humanity was confined to one continent, then this is totally possible. Even the possibility of humans surviving outside of Noah’s ark is discussed by the article, but I would refer the reader to the article itself for more information.
So in the end, there is justification for greater open-mindedness on the Great Flood. This of course is all speculation, but I have discovered that I am not the only one who has come to such conclusions. Browsing the internet, I see that many have come to the same exact conclusion as I have. In the end however, it remains a good though untested hypothesis. The past few centuries have shown zealous Christians digging a few thousand years into the strata, hoping to find a layer indicating a flood. The reality is a much greater distance may have to be investigated, and in an entirely different area.
Before I end this, I want to talk on the mechanism of the flood. Popular belief holds that rain was the predominant cause, but could rain alone garner the volume of water that is said to have wiped out virtually all humans? There is an often overlooked verse of the bible that needs to be carefully considered:
"In the six hundredth year of Noah’s life, in the second month, on the seventeenth day of the month, on the same day all the fountains of the great deep burst open, and the floodgates of the sky were opened".
The breaking up at the bottom of the sea has been interpreted as a tectonic event, and indeed it would have been a catastrophic one. At the bottom of the ocean there are expansive ridges where a great amount of geologic activity occurs. If you ever look at the shapes of continents, you will see they almost fit like puzzle pieces, as if they were once attached (e.g. the eastern coast of South American and the western coast of Africa.)
A slow and steady plate tectonic mechanism over millions of years is said to have placed the continents where they are today. But perhaps, through a Divine act, this process was invariably sped up to cause catastrophic geologic activity, including the movement of continents, volcanic eruptions, and displacement of vast amounts of the earth's oceans.
So we begin to see that Noah's flood may have been a far more complex event than simply 40 days of rain. The event would have reshaped the earth, caused volcanic eruptions that would ultimately lead into an ice age, and it certainly would have wiped out a significant population of the earth's inhabitants. Again, this is merely hypothesizing, but many of these points do fit nicely into the Genesis account. I offer this only to show that we need not be limited between fundamentalism and modernism, and that an open mind needs to be maintained when reading the bible, all the way defending its integrity and inspiration.