The city of Tulsa, Oklahoma, is slated to excavate part of a cemetery to search for a possible mass grave of African Americans murdered by white mobs during the 1921 Tulsa massacre — one of the worst events of racist violence in U.S. history. On June 1, 1921, a mob of more than 1,000 white people looted and burned the prosperous African-American neighborhood of Greenwood, often referred to as “Black Wall Street.” Thirty-five city blocks were completely destroyed, and as many as 300 people were killed. Eyewitnesses say truckloads of corpses were dumped into unmarked mass graves.