Most every culture has a story of a great flood. This happens regardless of where the cultures were located or the time period they were in. Do we have any idea if there was truth to this legend?

While more can always be said, we had a good discussion thread on this topic a couple months ago: Why is it that nearly every ancient culture around the world has a flood myth but a worldwide flood theory is not accepted by historians.. With answers by /u/Tiako and /u/commodorecoco and me elaborating on Japan's lack of a flood myth.