My family on my mom's side is incredibly long-lived (I'd really like to collect DNA from them and do a genomic analysis if I ever have some extra funding lying around) and it's exacerbated by the fact both my mom and my grandmother had kids when they were very young.
As a result, not only did I know all four of my maternal great grandparents growing up (most of them lived until I was well into adulthood), but there's even a picture of my great great grandfather holding me as a baby (he was like 105 when he died).
Even today, with me in my late 30s, both of my maternal grandparents are still alive and by all respects in very good health. It's pretty neat and I'm pretty fortunate to have had them as such a significant part of my life (and now my daughter's life as well). =)
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In Sandy we trust. Let's Go Mets! ^_^