Between 1760 and 1860, more than one million people who were enslaved were sold around the United States, according to University of Liverpool historian Michael Tadman in a February 12 article published in The New York Times MagazineThe Times Magazine revisited 12 sites where human beings were sold as part of The 1619 Project.

Anne C. Bailey, professor of history at SUNY Binghamton, joined forces with researchers from Binghamton’s Harriet Tubman Center for the Study of Freedom and Equity and photographer Dannielle Bowman to spend five months documenting archives, “including volumes of narratives of the formerly enslaved, as well as post-Civil War ads placed in newspapers by the enslaved themselves.” Baliey explained that she did the work in “an attempt to expand the historical record about America’s slave auction sites.”

The Times Magazine showcased sites from Georgia to Missouri to New York, but admits that the sample is small because there is no national registry that documented human sales. “To look at some of these images, which show former slave sale sites in the present day, is to grasp how invisible some of American history’s most grievous wounds have become,” Bailey wrote. “If we were to mark all these sites for posterity, we would help to heal their dark legacy, in much the same way that 19th century abolitionists, both Black and White, depicted the trauma of enslaved Africans on the auction block in their art and literature.”

To that end, The Times invites readers to share any information they have about former auction sites via a form at the bottom of the photo essay.