between the 7th and 20th centuries, the arab slave trade took 18 million slaves from africa via trans-saharan routes and the indian ocean. between the 15th and 20th centuries (a period of 500 years), the atlantic slave trade took an estimated 7–12 million slaves to the americas. while some africans collaborated with european and asian slave traders, many were strongly opposed to slavery and avoided, protested, or fought it violently.