JJ50,
I have seen, on the internet graves, with skeletons in them, that were, well over 15 feet. I do not know if these were fakes, or not.
According to the Bible account Methuselah lived 969 years, and Jared lived 962 years.
These people who lived extremely long lives were before the flood.
There seems to be two reasons for these extremely long lives. One was, before the flood, the people were close to the time that Adam and Eve sinned against God, so that the imperfection that sin caused, had not contaminated the bodies of the people, as it did in later years.
If people are found, that lived before the flood, not mentioned by Name, in the Bible, and they are thought to have lived extremely long lives, it could be because of the difference in the heavens, after the flood.
Before the flood there was, what the Bible called, a Swaddling Band, around the earth, which was a very thick cloud layers, Job 38:9. When anything on earth is living, it absorbs Carbon 13, and when a living thing dies thatCarbon 13 slowly dissipates. This means that a living thing living before the flood, and the rain from the Swaddling Band, would make the living thing that died before the flood appear much older, because it did not take in much Carbon 13, so there would e very little left. The living things after the flood absorbed much more, because the Swaddling Band was then gone, and they would appear much younger, because they would have much Carbon 13 still in their bodies.
There are many people named in the first few books of the Bible that lived much longer that we live today. This is because they lived much closer to the time mankind was perfect, before the Fall. This is also probably the reason that God allowed close relatives to marry. Being so close to the time of perfection, they would not be susceptible to deformities.