The 18th-century explosion in European sugar consumption was made possible by colonial rule in the West Indies and the enslavement of millions of Africans. Columbus carried the cane to Hispaniola (now Haiti and the Dominican Republic) on his second voyage in 1493. By about 1550, the Spanish and Portuguese had occupied many Caribbean islands and the coasts of western Africa, Brazil, Mexico, and were producing sugar in significant quantities; English, French, and Dutch colonists followed in the next century. By 1700, some 10,000 Africans were being traded via the Portuguese colony São Tomé to the Americas every year. The sugar industry was not the only force behind the great expansion of slavery, but it probably was the major force and helped ease its introduction into the southern American colonies and the cotton plantations. According to one estimate, fully two-thirds of the 20 million Africans enslaved in the Americas worked on sugar plantations. The intricate trade in sugar, slaves, rum, and manufactured goods made major ports out of the hitherto minor cities of Bristol and Liverpool in England, and Newport, Rhode Island. And the huge fortunes made by plantation owners helped finance the opening stages of the Industrial Revolution.