Whenever a submarine world was imagined in the Renaissance it took the form of a grotto. This pagan architectural topos was revived in fifteenth-century Italy and spread throughout Europe by the turn of the seventeenth century. Grottos were ubiquitous in early modern poetry and prose as well as in the gardens, palaces, and stages of cardinals and noblemen. They were a microcosm representing a submarine world mediated by the artistic and philosophical traditions of antiquity. With its rustic aesthetic imitating the look and feel of a natural space, grottos by the seventeenth century began to convey an empirical fascination with understanding and re-creating natural phenomena that gradually displaced the natural historical tradition that initially animated its fifteenth-century revival. In other words, grottos represent a time when a fascination with re-creating a rustic aesthetic inspired by antiquity catalyzed an empirical investigation of natural phenomena that gradually disproved the natural historical knowledge of the ancients. The origins of the Scientific Revolution can thus be traced in part to the shifting frontier between nature and art in the early modern grotto.