I'd find myself wondering how the people are and then coming to the realization they're all gone.....I just watched it with my 7 year old daughter. It was pretty cool way to talk about the concept of the past/history.
When hiking etc I come across wildlife, and years later recollect on these trips and the animals I came across, only the trees are still alive...maybe.I'd find myself wondering how the people are and then coming to the realization they're all gone.....