JEFF ROSENHEIM: Something remarkable happened about 185 years ago. It was kind of a celestial event that changed the world as we know it. It was the invention of a new medium. We called it photography.

Hi, I'm Jeff Rosenheim. I'm the Curator-in-Charge of Photographs here at The Metropolitan Museum of Art and I'm the curator of this exhibition.

NARRATOR: The exhibition you’re about to see features American photographs from this revolutionary new medium’s first seventy years. They come from a single collection, amassed by William L. Schaeffer, and they were donated to The Met by Jennifer and Philip Maritz.

ROSENHEIM: This exhibition explores the transformation of the country, of the United States, through the lens of photography.

NARRATOR: The majority of the photographs you’ll encounter have never before been exhibited. Most of the people involved—both behind the camera, and in the photographs—–are not famous. We don’t even know who many of them are.

ROSENHEIM: This rarely seen body of photographs are going to allow us to tell a new history of American photography.

Most art history is told from the top down, with canonized, bold-faced names. But this exhibition is expanding the canon dramatically. It's a tour of American photography from the bottom up.

NARRATOR: Throughout this Audio Guide, you’ll hear from curator Jeff Rosenheim, alongside other writers, artists, and cultural historians. We suggest you begin with the gallery to the left, where you’ll see some of the earliest photographs in the exhibition.

To hear how the poet Walt Whitman inspired the curator of this exhibition, listen to the next stop on the playlist.