Excavations began at the site of the massacre in Tulsa in 1921

At the site of a possible mass grave, which remained after the racial massacre in Tulsa in 1921, excavations began.

Local authorities have begun trial excavations to determine if the land owned by the city is a mass grave site.

Almost a century ago, Tulsa became the site of one of the most brutal massacres in US history. About 300 African Americans were killed by a mob of whites, and part of the city, known as Black Wall Street, turned to ashes. For decades, historians have tried to determine where most of the victims were buried.

Last year, experts using radar, discovered anomalies that could indicate the existence of an unnamed burial ground. Excavations will last 3-6 days, their goal is to find the remains. If analysts find traces of the burial, then work will continue.

From 150 to 300 African Americans were killed in the massacre.