Nation Researchers have found a possible mass grave in Tulsa. Could it be from the 1921 race massacre? December 17, 2019December 18, 2019Joel Shannon, USA TODAYComments Off on Researchers have found a possible mass grave in Tulsa. Could it be from the 1921 race massacre? The 1921 massacre, featured prominently in HBO's "Watchmen," happened when a white mob destroyed the 35-block "Black Wall Street" in Tulsa.