Twenty years ago, a group of college sophomores created a website that would end up changing the world — fundamentally altering how we connect with other people, how much we know about each other, and how we curate our existence. That website was Facebook.In the years since, Facebook quickly grew from a quirky site for college students to a global powerhouse — one that can affect everything from how we feel about ourselves to the outcomes of elections.On this episode, a look at Facebook as it turns 20 — its history, its ongoing impact, and what we really know about how it operates. We hear stories about a curious coincidence linking Facebook to a defunct government surveillance project, why many researchers have mixed feelings about Facebook, and how the website's ever-changing features transformed the lives and mental health of young people.