In the back rooms of the Smithsonian National Museum of Natural History in Washington, DC, are drawers upon drawers of exotic bird carcasses, cultural artifacts, hunks of rock, and much more.

For over two decades the museum has preserved more than 90% of its collection in these rooms, sorting each natural wonder down to the color of its feathers or the era from which it hails — all for the sake of keeping history alive.

Over the course of 17 years, the museum's chief photographer, Chip Clark, snapped photos of these collections and the people who maintain them.

Take a step inside.