A single tree. An uncultivated patch of farmland. What do these places reveal about a brutal chapter of American history? They lead us to the forgotten burial grounds of thousands of enslaved people. “This whole region, it’s like a land of lost cemeteries.” Using a system of maps that goes back nearly 150 years, we can see evidence of cemeteries on Louisiana’s former plantations. These graves are scattered along the Mississippi River where petrochemical plants now dominate the landscape. We went to Louisiana to investigate these sites from the ground, from the air and from space, and spoke to local residents about their quest to preserve these graves before they’re lost forever. “On a plantation, this was your freedom. You didn’t get freedom until you were dead in your grave.” Darryl Hambrick and his sister, Kathe, run the River Road African American Museum. They learned about the region’s lost cemeteries through their work as historians and funeral directors, and have been identifying them for the past 30 years. “There needs to be a place that’s protected in the memory of those people who were enslaved here.” “These families’ lives were bound to this land because of plantations. They were brought here to work these plantations and remain here and die here and be buried here.” It’s easy to identify a cemetery that has headstones, but enslaved people used whatever materials were at hand. “Sometimes, they would mark it with a tree, or there would be very few markings, maybe a wooden cross.” This is part of the reason they’re so hard to find. Trees become a part of the landscape over time. Wood crosses decompose. “When something is invisible or somewhat imperceptible, it’s easy to claim that it doesn’t exist.” Imani Jacqueline Brown is a researcher with Forensic Architecture, a London-based group that applies visual and spatial investigative techniques to issues ranging from wars to climate change. “I grew up in Louisiana and worked as an environmental activist and as a fossil fuel accountability activist for many years. And, when I thought about what lay beneath the ground, I mostly thought about pipelines. I never thought about the graves of historically enslaved people, some of whom are very likely to be my ancestors.” Using layers of maps, Forensic Architecture has created a kind of time machine to help find these unmarked burial grounds. “By toggling these layers on and off, we can travel through this sort of wormhole.” Here’s how it works. Look at these maps from 1878. They were created for the U.S. Coast Survey to aid in navigation, up and down the river. But look closer, and you can see other important clues about what the land was used for at that time. Some of the symbols are abstract, but some are very clear, like this pair of crosses. “The cross indicates the presence of a cemetery. From there, we jump for a period of about 65 years to the first aerial photography.” In 1940, the U.S. Department of Agriculture took a series of aerial photographs of this region. In the same spot we saw the crosses, we now see a clump of trees. Researchers call this an anomaly. “An anomaly is a topographical feature that seems out of place in a landscape. It can be an uncultivated patch of land. It could be a grove of trees.” As we move forward in time, we can see that the grove of trees gets smaller, but the anomaly persists. “When we look at a contemporary satellite image, we see a single tree standing alone amidst a sea of sugar cane, and we recognize that this is a site that should be investigated as a potential cemetery.” Forensic Architecture has located more than 1,000 anomalies in the 1940 aerial imagery, but many have since disappeared. Only 329 can still be seen today. “Ultimately, if a patch of land is uncultivated, there’s a reason for it.” “To most people, and I guess even to us, they look just like fields.” Don Hunter is an archaeologist who has been working in the region for decades. He’s used these maps to identify cemeteries on industrial expansion projects. “There’s a cemetery right there in front of you. You’ve got to look hard.” His previous work inspired Forensic Architecture to develop this mapping system for a larger area along the Mississippi River. “There are thousands of these things out there, potentially. Unless steps are made to put more effort into identifying these sites and protecting them, we’ll continue to lose them.” The only way to fully confirm the anomalies is to do an archaeological dig. “The biggest obstacle to doing this type of research, first of all, is money. It cost money to go out and dig holes in the ground, and nobody wants a cemetery in their backyard for various reasons.” Louisiana’s laws state that any known cemetery must be cordoned off and protected, but these laws didn’t exist when petrochemical companies first started buying up plantations. “They started buying up the property because they need access to the river just as the plantations did.” “Over 200 plantations and counting are now petrochemical plants, and these cemeteries are now being crushed by these petrochemical plants.” Because these sites are on private property, they can only be accessed with the landowner’s permission. Forensic Architecture’s research shows us where some of these suspected sites have already been affected. Some have been plowed over. Here is one in an oil refinery and another beneath a retention pond. “The confidence level in the locations on the Coast Survey maps are so high that I would bet anything that it’s there. It’s under the pond.” Most companies have not publicly acknowledged burial sites on their property. The number that have worked with the community to preserve them? One. “It’s been 25 years of trying to contact Texaco and Star Enterprise and Motiva and Shell. I would get no response — ” — until Shell got back to Kathe in 2013. The company confirmed the existence of two cemeteries and wanted her help to preserve them. But one cemetery had already been destroyed by years of plowing. A company report found small human bone fragments across an entire field. The other cemetery stood forgotten as a grove of trees in the middle of farmland. “The archaeologists estimate that there are as many as 1,400 graves between those two cemeteries, alone.” Images from the site show the grave of an infant found along with a single white button. Archaeologists believe it may have been placed on top of the coffin at the time of burial. In 2018, Shell fenced them off and made them accessible to descendant communities by appointment only. How companies choose to preserve cemeteries found on their property has been at the center of a battle against a new 2,400-acre plastic facility in St. James Parish. “Here, where you see that partial fence that’s going around the grave site, that’s Buena Vista grave site, the site with our ancestors in that ground right over there. And we are not allowed to go on that property.” Sharon Lavigne, a local activist, has been leading the fight against Formosa Plastics, which wants to build an ethylene cracking complex two miles from her home. Formosa has identified and investigated two potential cemeteries. They found human remains at one, and fenced it off. Another possible site identified by various researchers hasn’t been looked at. The company says it will always be respectful of the burial remains discovered on the property, but it’s not only the burial site Sharon is worried about. She says this new plant could cause further harm to the predominantly Black community that lives in this area. “The chemical that they’re going to use to make the plastics is cancer-causing. Ethylene oxide, that’s cancer-causing. Benzene from formaldehyde, that’s cancer-causing.” The Environmental Protection Agency has highlighted how communities of color are disproportionately affected by high pollution levels. According to the E.P.A., long-term cancer risk in St. James Parish, where Sharon lives, is three times higher than the national average. “Racism and structural racism is a largely invisible force that pervades our society. During the antebellum era, sugar cane was notorious for being the most dangerous crop to cultivate. Today, these freetown communities are at the fence line of some of the nation’s most polluting petrochemical facilities.” “Now, the landscape is Black community, chemical plants, sugar cane fields, Black community, chemical plant. It makes me very sad, but I want to preserve what’s left.” Remember this tree? It marks a cemetery at the former Point Houmas plantation. Enslaved people could be buried here. Today, it’s for sale as part of a future industrial site.