A friend I had met as a 15 year-old in summer camp and then again at an internship at 20 was visiting Denver this week for work. Even though he and I have never been completely out of touch and do not reunite every seven years exactly, our friendship reminded me of the great documentary series 7 Up! I recently rewatched 49 Up! in anticipation of his visit. I suggest you do the same, or if you know nothing of this program, start at 7.

The series is based on the Jesuit maxim, “Give me a child until he is seven, and I will give you the man.” What started as an examination of the British class system in 1964, has continued for 42 years as an exploration of 12 people’s lives in seven year increments. Of all the cultural experiences I’ve had, I can’t think of one that’s affected me more. Even though I don’t know these people in a real way, I’ve also known them for 42 years. There’s a value in just the length of that relationship, and in some ways, the films made me understand and appreciate family in a way I hadn’t before.

If you’re curious about people and time, this is a good movie. Plus, 56 Up! will be released in America early next year, so you won’t have to wait seven more years to see how later middle age has treated these people.