100 year reset ?

Hey everyone i had a conversation with my grandmother last night(she is anti conspiracy theories) and i told her i wished i could have talked with my grandfather(he passed away 18 years ago) about whats happening in the world right now as he went around the world with the marines on boat. Then she said about that he said to her that humanity resets every 100 year. Keep in mind this was all before internet and such things. I know ive read a story about something like this here on reddit. If anyone knows more about this please share in the comments

Edit : Wow thanks for all the responses im gonna read them all now !!