On Monday, the Alexandria city government announced plans to purchase and renovate Freedom House, an Old Town museum that was once the headquarters for the largest domestic slave trading firm in the nation, Franklin and Armfield.

The museum recants the brutal conditions of life in the former slave pen through first-person accounts, and examines Alexandria’s significant role in the slave trade with bone-chilling replicas of shackles and whips.

Today, the building at 1313 Duke St. is hardly distinguishable from other 19th century row houses in Old Town—but the authors of Chocolate City: A History of Race and Democracy in the Nation’s Capital write that in the 1820s and 1830s, it was impossible to miss:

“It was indeed a prison, a holding pen for enslaved people from across the Washington area before they were sent ‘down river’ to slave markets in New Orleans and Natchez, Mississippi.”

Franklin and Armfield sold more than 1,000 slaves a year and retired rich, while the Duke St. slave pen changed hands. At one point, it was run by James H. Birch, the Washington slave trader who kidnapped and sold Solomon Northup, of the film 12 Years a Slave, based on his memoir.

The basement-level museum has faced serious financial troubles for years, and the city’s office of historic Alexandria took over museum operations in February. The Northern Virginia Urban League, the non-profit group that has owned the museum for over a decade, put the building up for sale in October.

On New Year’s Eve, the city of Alexandria reached a $1.8-million deal with the non-profit, which will still have office space in the building.

Diane McLaughlin, chair of the Northern Virginia Urban League’s board, said in a press release that “The League will continue to focus on its primary mission to enable minorities and other disadvantaged communities to secure economic self-reliance, parity, power, and civil rights.”

Mayor Justin Wilson added in the release that the city plans to partner with the state and private donors to improve the building and museum. He said the preservation of sites like Freedom House helps to “connect the stories of our past to our present day conversation about race and equity, and ensure we are telling a broader, more candid account of Alexandria and our nation’s history.”

In December, Governor Ralph Northam added more than $2.4 million to the proposed budget for the Commonwealth to expand the museum from the basement to the building’s upper floors.

The Alexandria City Council will vote to make the purchase official in February.