The Stone Age.
My daughter came home from school telling me all about the stone age that happened millions of years ago.
I smiled and reminded her that Daddy likes to go arrowhead hunting in the fields.
I expanded, "The arrowheads were crafted out of rocks. They chipped away at larger rocks to make them sharp, then tied them onto a thick stick for an axe. Their spears where simply long sharpened sticks."
She nods again.
"Native Americans still used those tools in the early 1900's, less than 100 years ago!"
Her eyes grow wide.
Moral of the story: The stone age is closer than the history books tell you.