Vacant and blighted urban land is a widespread and potentially risky environmental condition encountered by millions of people on a daily basis. About 15 percent of the land in U.S. cities, more than 9 million acres, is deemed vacant or abandoned, an area that is roughly the size of Switzerland. Urban residents, especially in low-income neighborhoods, point to these spaces as primary threats to their health and safety while cities seek meaningful, evidence-based interventions for once vibrant but now vacant land. A team of scientists that included Michelle Kondo of the NRS conducted what team members believe to be the first citywide cluster randomized trial testing the effects of inexpensive, standardized, and reproducible vacant land remediation interventions—namely greening and trash cleanup—on health and safety. In a study published in the Proceedings of the National Academy of Sciences, Kondo and her co-authors assigned 110 vacant lot clusters in Philadelphia, PA, containing 541 vacant lots, to one of three study groups: the greening intervention, the trash cleanup intervention, or the control group where no intervention occurred. Eighteen months after greening projects began, 342 residents in neighborhoods that were at or below poverty reported significantly reduced fear of crime, and increased use of outdoor spaces for relaxing and socializing. There was also a significant decrease in crimes overall, in gun violence, burglary, and nuisances near the treated lots compared to near the control lots.