I can't think of a better way to phrase this, but my gist is - a person born in 1900 who lived a long life of 100 years (for neatness sake) would have seen so much change. When they were a teenager, the Great War is happening, in their 40s, the Second World War. When they're in their sixties society is changing all around them, then they see Thatcher in the 80s and by the time 2000 rolls around, the internet has happened. The world of 2000 is such a radically different place from the world of 1900, it's staggering to me that someone could have lived through both.
Do you think there are any other lifespans a person could have had that would match that? Perhaps someone born in 1750 living to 1850 would watch the Industrial Revolution happening, the Napoleonic wars etc.