The document discusses the Trans-Atlantic Slave Trade which began in the 17th century. Plantations in the Americas and Caribbean demanded labor, and Africans were forcibly taken to these colonies as slaves. It is estimated that millions of Africans were transported this way by the 18th century, with the numbers doubling from the 17th century. While slavery had existed in Africa, the slave trade with Europeans industrialized and vastly increased the scale. Africans were often captured from other tribes or cultural groups and sold on the coast to European traders. The transport of enslaved Africans across the Atlantic became known as the Middle Passage. The slave trade profoundly impacted societies and economies in both Africa and the Americas.