March on Washington participants. Aug. 28, 1963. (Courtesy Library of Congress)

Beyond the unifying symmetry of the numbers, what binds and animates the new “Changing America: The Emancipation Proclamation, 1863, and the March on Washington, 1963” exhibit at the Smithsonian’s Museum of African American History and Culture gallery is the great press of American people toward freedom.

It is a constant, relentless force before, during and after these iconic moments in history, with a sweep that is nationally momentous and deeply personal. It winds between the artifacts, giving them weight and suasion.

The gallery, inside the American History Museum, divides into two sides and organizes around a quote from labor and civil rights leader A. Philip Randolph: “Freedom is never given, it is won.”

To the left of the quote is the distant history of slavery and the Emancipation Proclamation, to the right is recent history, the March on Washington, such that visitors who were there will look to try to find their faces.

“Looking at these two moments in time, these two kinds of struggles for inclusion, freedom and participation, you see more than 100 years,” said Harry R. Rubenstein, co-curator of the exhibition. “You see the history of the nation.”

An unidentified soldier in Union uniform poses with his wife and two daughters. Many African Americans celebrated emancipation by formalizing their marriage—an act denied under slavery. (Courtesy Library of Congress)

The Emancipation Proclamation side of the exhibition begins with slavery. “Enslaved people were valued at an estimated $2.7 billion in 1860,” reads a panel, and the nation protected its treasure with violence. There is a slave whip and an auction notice for a family of six. A pair of iron shackles for a small child conjures such a horror that co-curator Nancy Bercaw catches her breath as she talks about it.

Slaves resisted with acts of defiance. In 1831, Nat Turner’s rebellion killed 55 whites in Southampton County, Va., and the exhibit displays the Bible he was holding when he was captured. A handbill offers a $100 reward for a runaway slave: “My negro man named Dick, commonly called Richard Law, ran away from my residence in Upper Marlborough, Prince George’s County on the morning of the 18th of July.”

Maryland was not affected by the Emancipation Proclamation, which didn’t free slaves in border states and areas under Union control, Bercaw says.

African American History and Culture Museum Director Lonnie G. Bunch III calls the large “Contraband Tent” among his favorite artifacts. These tents housed the tens of thousands of “self-emancipated” slaves who escaped to the Union lines as soon as the war began and proclaimed themselves free, forcing Lincoln and the Union into action — to return them to slavery or recognize them as free.

“They said, ‘I ain’t waiting for you,’ ” Bunch said. While “it’s crucially important to celebrate Lincoln as the man who said ‘forever free,’ the slaves weren’t passive recipients of freedom,” but they instead agitated, prodded and were central to it. “That’s what I want to get across.”

President Abraham Lincoln’s black broadcloth coat, vest and trousers are displayed, along with the top hat he wore the night he was assassinated at Ford’s Theatre. The exhibit also features the lone copy of Lincoln’s handwritten 13th Amendment ending slavery in the United States. Medals and ID tags of black soldiers, the pen used by Ulysses S. Grant to sign the 15th Amendment, which guaranteed the right of black men to vote, exist along a continuum that includes poll taxes, the rise of the Ku Klux Klan and other racist retrenchments.

It is part of the constant contradiction of American history that leads visitors toward the March on Washington section on the other side of the gallery, several feet away.

Beginning with the dedication in 1922, the Lincoln Memorial became the national staging ground for civil rights protests. These include the 1939 Easter concert by Marian Andersonafter the singer was barred from singing in Constitution Hall.

The 1957 Prayer Pilgrimage for Freedom marking the third anniversary of the Brown v. Board of Education Supreme Court decision desegregating schools was a training ground for leaders of the 1963 march, including Randolph, Bayard Rustin, Roy Wilkins and Martin Luther King Jr.

Images on the walls show a montage of demonstrations and events in 1963 leading up to the march — including Gov. George C. Wallace barring the doors to the University of Alabama, the funeral of slain civil rights activist Medgar Evers. There were more than 1,000 demonstrations and events.

A budget includes the salary for Rustin, arguably the most-important, least-known civil rights figure, who was tasked with logistics for the 1963 March on Washington: “10 weeks @135/week.”

Schedules, bus fliers and maps help detail the movement of an estimated 250,000 people onto the grounds of the Lincoln Memorial. Black singers Anderson, Mahalia Jackson and Odetta were joined by white folk singers, including Joan Baez, who sings “we are not afraid” on grainy black-and-white video from the day. Baez’s guitar is displayed, along with a list of the Hollywood delegation to the march, co-chaired by Charlton Heston. Stars who came included Burt Lancaster, Judy Garland, Kirk Douglas and Marlon Brando.

Buttons, programs, maps and pennants provide the slogans and assertions of people who voted with their feet. Who had shown up, amassed and demanded equal everything, “Now!”

A simple pocket watch inscribed “From Martin to Bayard for Aug. 28, 1963” helps memorialize the day. As does an inscription from writer James Baldwin: “That day, for a moment, it almost seemed that we stood on a height, and could see our inheritance.”

The exhibit featuring two moments of American history is separated by 100 years and by a small lobby area filled with quotes and statistics and faces. It offers visitors time to pause and reflect before continuing on in the great, unending American press toward freedom.

Changing America: The Emancipation Proclamation, 1863, and the March on Washington, 1963

Runs through Sept. 15 at the National Museum of African American History and Culture Gallery at the National Museum of American History, 14th Street and Constitution Avenue NW. 202-633-1000.