Monday (June 19) will mark Juneteenth, the celebration of the end of slavery in the United States. In commemoration of that day—and recognition of the current war Black people wage daily in search of true freedom—organizers with The Movement for Black Lives will hold a day of action meant to reclaim space.

As NPR’s Code Switch noted in a story in 2015, Union General William T. Sherman’s Special Field Order 15 promised newly freed slaves “a plot of not more than forty acres of tillable ground,” to be taken from confiscated Confederate land. As of January 16, 1865, this order was known as “40 acres and a mule.” But after President Abraham Lincoln was assassinated, President Andrew Johnson reversed the order, leaving the promise unfulfilled. The reverberations of that action are still felt today.

From an emailed statement on Monday’s action:

From vacant lots to empty school buildings, Black people across the country will take back land that should be used for the good of the people: land that Black people have been historically been denied access to. Through national efforts to collectively reclaim 40 acres in 40 cities, the actions aim to confront the institutions that have been built off the extracted wealth of Black people and Black land, and the individuals who have profited from them.

Created as part of the year-long Black Land and Liberation Initiative, the nationwide actions will focus on making spaces work for the people who need them most.

“People will take over spaces by entering, cleaning, reclaiming and opening, abandoned buildings, vacant lots and local spaces that are critical to local communities across the county,” Chinyere Tutashinda, lead organizer and co-director of the BlackOUT Collective, told Colorlines.

The 40 cities will include Atlanta, Chicago, Detroit, New Orleans, New York City, Oakland and Philadelphia. Find an action near you at M4BL.net.