What was the Middle Passage? Where did it begin and where did it end(regions/continents)?

What was the main cargo during this passage?

Middle Passage, the forced voyage of enslaved Africans across the Atlantic Ocean to the New World.  The first known transatlantic slave ship—sailed from São Tomé to New Spain in 1525, outsourced by Genoese bankers who paid the Spanish court for the Asiento de Negros. Till 1640, Portuguese slavers had a near monopoly on the export of slaves from Africa. The First Passage was the transportation of captives (slaves) to the African ports, such as Elmina, where they would be loaded onto ships. The Final Passage was the journey from the port of disembarkation, such as Charleston, to the plantation or other destination where they would be put to work. The captives were about to embark on the infamous Middle Passage, so called because it was the middle leg of a three-part voyage -- a voyage that began and ended in Europe. The first leg of the voyage carried a cargo that often included iron, cloth, brandy, firearms, and gunpowder.