Portrait of young Harriet Tubman unveiled at National Museum of African American History and Culture

A new exhibit opened today at the National Museum of African American History and Culture. It's a never-before-seen photograph of one of the most famous women in U.S. history.

The Harriet Tubman most of us have come to know is from photographs of the abolitionist as an older woman -- but on Monday, the Librarian of Congress and the director of the National Museum of African American History and Culture unveiled an image of the Underground Railroad conductor never before seen in public. It is the earliest known photo of Araminta Ross -- better known as Harriet Tubman.

"When you look at that image, you suddenly see somebody who's vibrant. Somebody who you could imagine leading people through the wilds of freedom, actually spying for the union. Somebody who had that dedication and that strength," said NMAAHC director Lonnie Bunch.

"We hope young people will be inspired and will really get a sense of this was the woman who led 300 people to freedom," said Dr. Carla Hayden, Librarian of Congress.

The museum and Library of Congress together bid on what's known as the "Emily Howland Photo Album" at auction. It had been in a private collection.

"This is a treasure trove, if you will, of about 49 images -- Portraits of different people really involved in education, in activism, in abolitionism," said Rhea Combs, curator of photos and film at NMAAHC.

Included in the album is the only known photograph of John Menard, the first African-American elected to the U.S. House of Representatives.

Descendants of Harriet Tubman were at the unveiling ceremony, including Deborah Brice. She told FOX 5 she only made the discovery recently while researching her family's genealogy.

"I think her determination not to stand by and be satisfied with her lot in life and to move forward and to achieve it and not only for herself, but thinking of her brothers and sisters, moving them out and other slaves," said Brice.

The album and the Tubman portrait will be on display in the museum's Heritage Hall for the next week. It will eventually be relocated to an exhibit on slavery and freedom. You can also view and download the photo on the websites of the Library of Congress and the NMAAHC.