This study investigates the role of the natural environment in Spain's colonial project in the Americas during the sixteenth through eighteenth centuries. My project focuses on the cultural and intellectual conceptions of volcanoes among Nahuas in central Mexico, Kaqchikel Maya in highland Guatemala, and Spanish conquistadors, priests, and naturalists. Prior to Spanish arrival, Kaqchikel Maya and Nahuas maintained complex economic, cultural, and socio-religious connections, which included shared perceptions about their volcanic homelands. They considered these often-volatile landscapes as animate members of their communities, believing that volcanoes housed their deities and ancestors and that rivers originated from within them. Unfamiliar with this topography, Spaniards relied on their preconceived ideas about sacred mountains and indigenous guides as they became accustomed to this new terrain. Volcanoes became sites inscribed with multiple meanings – perceived as both sacred and demonic, creative and destructive, and marvelous and dangerous. This project combines ethnohistory with history of science to examine how the dynamics of conquest and colonization shaped perceptions of the natural environment. It uses archival documents, natural history treatises, chronicles, indigenous codices, cartographies, and engravings to evaluate how indigenous and European actors engaged with the landscape socially and intellectually. My project interprets the landscape beyond acting as a mere stage that hosted Kaqchikel-Nahua-Spanish interactions. It proposes that volcanoes and lakes should be considered as historical actors in the dynamic processes of colonialism. By privileging indigenous knowledge about the environment, this project expands the traditionally accepted geographic boundaries of early modern knowledge production. Finally, it emphasizes the importance of indigenous knowledge in nascent natural histories.