The remains of 20,000 African men, women and children have lain beneath the busy streets of New York for 300 years, waiting to tell their stories on the extent of slavery in the city.
Evidence from the burial site revealed, for the first time, the enormous human cost of such work.
Half of the remains were of children under the age of 12. Women were usually dead by 40.
"It seems that it was cost effective for slave traders to work people to death and then simply to replace them, so they sought to get Africans who were as young as possible, but ready to work," said Mr Blakey.
From royalty to slavery? Read more...