It is amazing how much evidence there is in the world for a flood that covered the entire earth. Just like the Bible says happened in the days of Noah. You can read the story in Genesis 6:1-9:17. Lets look at a few of the events of the flood first:
Genesis 7:20
The waters prevailed fifteen cubits upward,
and the mountains were covered.
The Bible says that the flood was deep enough to cover the highest mountain under 20 feet (15 cubits) of water. Probably the mountains were much smaller, because in Psalms the Bible describes the mountains and valleys being made during the flood. Is it possible for the tallest mountains to be under water? When people started climbing Mt. Everest (the tallest mountain in the world) they found that the very top of the mountain is covered in fossil sea shells, like clams and mollusks. How did they get there? The Bible says that the highest mountain was under 20 feet of water - I think that explains it very well!