Cities are complex organisms shaped by myriad forces, but their organization bears the fingerprints of planners and policy makers who have shaped them for decades.

At the root of many of these practices is racism, and modern cities bear the legacy of that discrimination. In an era of social protest, when movements like Black Lives Matter are bringing inequality back into the national conversation, it's time to reassess the practices that have perpetuated these problems—and how we fix them.

But the first step is understanding the urban policies that got us here. For decades, planners slashed through neighborhoods in the name of urban renewal and slum clearance, underwritten by federal funding from the Housing Act of 1949 and the Federal Aid Highway Act of 1956, displacing residents using tactics like eminent domain and condemnation laws.

As a result, much of our highway system courses through black neighborhoods (which helps explain why they've often become spaces of civil protest). "This method fails," wrote grassroots urbanist Jane Jacobs in the Death and Life of Great American Cities, one of the most influential planning books ever written.

"At best it merely shifts slums from here to there, adding its own tincture of extra hardship and disruption. At worst, it destroys neighborhoods where constructive and improving communities exist and where the situation calls for encouragement rather than destruction."