In Tulsa, Oklahoma, archaeologists have found a mass grave containing at least 10 coffins during a search for victims of one of the worst massacres of African Americans in U.S. history. In June 1921, a white mob burned to the ground Tulsa’s affluent African American neighborhood of Greenwood, known as Black Wall Street, killing at least 300 residents. Investigators have not confirmed if the bodies found in the unmarked grave are victims of the massacre.