The Portuguese Empire was built throughout the 15th and 16th centuries, driven by advances in navigation and a desire for trade, territorial expansion and evangelization. Pioneers such as Vasco da Gama opened new routes to India, transforming Portugal into a maritime superpower. Through the trade in spices, gold and slaves, the Portuguese established colonies in Africa, Asia and South America, including Brazil. Despite its initial success, the empire faced native resistance, conflicts with other European powers and controversies such as the slave trade. In the 20th century, the empire declined, and decolonization culminated in the Carnation Revolution, ending Portuguese colonial rule in 1974.