Nearly 100 years ago, a white mob destroyed an American neighborhood called “Black Wall Street,” murdering an estimated 300 people in Tulsa, Oklahoma. That incident — known as the 1921 Tulsa Race Massacre — has been largely left out of US history books. Today, a century later, the city still has a lot of questions. For one, where are the bodies of the victims? As the city’s mayor re-opens the search for mass graves, we take a look at what happened back in 1921…and why finding these graves still matters to the people of Tulsa.