During the period 1492-1750, the Atlantic world underwent social and economic transformations due to new contacts between Western Europe, Africa and the Americas. Some social changes that occurred between the Americas and Africans were the transformation of the Indies and Africans to the lowest level of the social structure and the creation of new classes, such as the mulatto class, all because of Spanish dominance. The economic transformations that occurred were the creation of sugar plantations and gold mines, creating brutal labor for African slaves and American Indians. A continuity that remained throughout the period was that of basing the economy on agriculture. As Spain and Portugal began to dominate the Eastern Hemisphere, a new social structure began to take shape. The Spanish obviously belonged to the upper classes of the new colonies as they dominated Indian societies due to their cruelty and weapons. The new classes that emerged were peninsular, creole and mestizo. Peninsulars were Spaniards born in Spain and constituted the highest class of the social structure. The Creoles came after the Peninsulars. They were Spanish parents born in New Spain. After the Creoles came the mestizos who were Spanish parents and Native American Indians. The Native American Indians came after the mestizos. At the basis of the social structure were slaves brought from Africa and the Caribbean. The social structure was full of miscegenation, creating a new type of social structure because most countries are made up of one race like in China, Japan and France. However, Indian nobility remained throughout the period. At first, Brazil was irrelevant to Portugal because the only thing they found useful there was their lumber. However, sugar began to develop in Brazil. Since sugar was introduced to the Caribbean in 1493, Brazil became the largest sugar producer in the 15th century. Brazil was the first sugar plantation colony with the help of the Portuguese and especially the African slaves. During the 17th century, approximately 7,000 slaves were imported from Africa to Brazil, to be forced to work in sugar factories. The forced labor was brutal and the conditions were terrible. They were unsanitary and dangerous, because slaves had to cut sugar canes as close to the ground as possible. Because of this, many lost fingers and legs. However, Brazil lost its dominance of the sugar market in the 17th century because the English, Dutch, and French established their own plantation colonies in the Caribbean and produced sugar in the 1680s..