In 1971, a highway construction project in Maryland unearthed a mysterious burial site. Construction was halted. A local historain was brought in, who quickly determined this was a cemetery dating back to the Civil War. It contained the remains of over 100 enslaved African-Americans who worked at the nearby smelting furnace known as Catoctin.

Catoctin furnace is located a few miles from Camp David in Cunningham Falls State Park. It was first established in the 1760s then slowly grew into a village complex, with industrial buildings and housing. Workers mined iron ore, kept the furnace burning and made various goods - stoves, pots, utensils and even cannon balls. Enslaved people dominated its labor force until hiring European immigrants became cheaper by the mid-19th century.

Who were they? And what happened to this vanished community? In a first-of-its-kind analysis, the researchers examined historical DNA alongside genetic testing company 23andMe's personal ancestry database to identify 41,799 Americans related to the 27 individuals, including 2,975 close relatives. Their findings did more than confirm their identities, but gave a detailed snapshot of an American slaves life. We learn what they ate and drank, how they worked and lived, and how they died.

CATOCTIN: FORGED IN SLAVERY examines historical documents, bones, and uses the latest scientific equipment to learn more about these forgotten workers and the uncredited role they played in fueling America's Industrial Revolution.