Editor’s note: This story originally aired on The World earlier this year as part of the series, “400 years: Slavery’s unresolved history.” It was repackaged on the show again on Nov. 29 as part of a special feature over the holidays along with this story.

Over one doorway at Elmina Castle, a former hub of the slave trade in Ghana, a brass plaque reads, “door of no return.” It was the last door that captive Africans went through in Africa before they were boarded onto ships and sold as slaves.

The passage is intentionally narrow, so prisoners had to walk one by one through the near darkness and then into the sudden, blinding sunlight. From there, the captive Africans were chained for months in the packed bowels of ships until they arrived in the Americas, and were enslaved.

Click here to see the full essay in PRI.