Central and South American civilizations such as the Mayans, Aztecs, and Incas developed advanced cultures prior to European contact, with accomplishments in mathematics, astronomy, agriculture, and urban planning. However, their political systems differed from European monarchies, and their ideas of leadership and warfare clashed with Spanish conquistadors like Cortés and Pizarro, leading to conflicts and the decline of these civilizations as Spain built its empire in the Americas in the 1500s and 1600s. Concurrently, factors in Europe like improved navigation and nation-state competition drove expansion and exploration across the Atlantic.