Nolan Krentz’s life is built around playing golf: Seventy-two holes a day is normal for him in the summer; 36 is a disappointment. Last year, he played 18,018 rounds, nearly all of them on his nine-hole course in Wisconsin. It wasn’t enough. So what makes him so driven? Check out our feature to learn more about Krentz’s obsession to play more than 18,000 holes in a year.