One of the first paintings on display at the Smithsonian National Portrait Gallery shows a woman in a bright red dress with a motherly smile. Her neatly manicured hands are shown gently clutching a Bible.

The painting depicts Henrietta Lacks, a mother of five who died of cervical cancer in 1951. She unknowingly became a part of history when, during her treatment, doctors removed some of her cancer cells to be used for research. The results would go on to revolutionize medicine and play a key role in developing the polio vaccine, saving millions of lives around the world.

“She’s such a huge figure in American history that we don’t really know about,” said Kadir Nelson, the artist behind the Lacks portrait. “And hopefully, this painting will help spread that story.”

As the National Portrait Gallery celebrates its 50th anniversary, curators are making some changes to the collection. Their intent is to include more faces of color and figures who are typically excluded.

Nelson’s portrait of Lacks at the Smithsonian Institution is part of that effort. Together, the National Portrait Gallery and the National Museum of African-American History and Culture commissioned the artist to create a portrait to be shared between the two museums.

Months after his work was unveiled, Nelson entered the gallery on a quiet summer morning to view his work in its new home for the first time. In an exclusive interview with NBC News, he explained why he hopes his work will serve as a history lesson to viewers.

“The idea is that when you walk by the painting, you’re stopped in your tracks,” he said. “Not only because it’s beautiful, but because it reminds you of something. It draws you in and makes you think for a minute.”

The portrait hangs just inside the gallery’s main entrance, in the same spot that initially housed Michelle Obama’s portrait. It’s a prominent location.

And according to Dorothy Moss, associate curator for the National Portrait Gallery, that is exactly the point.

“We wanted to acknowledge that we are making a true effort to show the stories of people whose lives have been left out of textbooks,” she said. “Whose stories have not been known broadly until recently.”