Bill Bonner has seen hundreds of thousands of photographs during his 31 years as the archivist at National Geographic. In fact, he watches over some eight million images in the vintage collection.

Before I met Bill, I thought I knew what having a photographic memory meant—you know, being able to remember everything you see. But he showed me another side, one that is literally filled with memories, both simple and important.

Bill works alone, in a cold windowless room in the basement of National Geographic’s headquarters in Washington. But even though he spends the days mostly by himself, he says he is kept company by the millions of people immortalized in the photographs. To him, they are his ancestors, and he treats