Harry Potter.
As you read this name, I know you're already imagining "Hogwarts" in your mind - or maybe it's just me. Anyways, who doesn't even know about it? Well, I guess there are some but most of the people living on Earth know it (and some are actually addicted to it) due to its fame and magic.
As we all know, the Harry Potter book series are adapted to movies which made it more popular to millenials, and as of now, the Harry Potter vibe still exists even on the internet, especially on social media sites.
The existence and success of Harry Potter will never happen if this person never had her persistence in the first place, and you know who that is - J.K. Rowling.