The African Burial Ground National Monument is the final resting place of approximately 15,000 African New Yorkers. In use until 1794, it was the holiest place in New York for men and women of African descent. It was rediscovered during construction of a federal office building in 1991 and is regarded as the most important urban archaeological discovery of the twentieth century. The African Burial Ground was designated a National Historic Landmark by the Secretary of the Interior in 1993, and it is listed on the National Register of Historic Places.