Exploring the Mesoamerican Subterranean Realm brings together the latest work and interpretations on the use of underground cavities by Mesoamerica's pre-Columbian cultures, demonstrating their invaluable cultural purpose. Case studies from across the region investigate the ways in which these highly charged points in the sacred landscape were the focus of countless political and religious activities. The volume expands the study of caves to focus on the broader realm of subterranean space, introducing the concept of the constructed subterranean, a space in which the Maya deliberately created sacred landmarks through excavation. Chapters critically examine chultuns, previously thought to be subterranean storage chambers, and sascaberas, previously considered mines, demonstrating that the traditional archaeological models are fatally flawed. A wealth of data on both features is used to envision a new sacred landscape filled with thousands of subterranean sacred landmarks. Natural caves are also examined; a survey conducted around the ancient site of Yaxchilan considers the obvious importance of large stalagmites set up in the site core as monuments. Long-distance pilgrimages to these caves fundamentally reevaluates the nature of pilgrimage and reveals an economic and political importance that structured settlement and activities around the pilgrimage sites. Finally, evidence is analyzed to show that the human bones recovered from Midnight Terror Cave, Belize, were the result of human sacrifice. Dealing equally with the archaeology of both natural and constructed subterranean spaces, Exploring the Mesoamerican Subterranean Realm challenges preconceived notions of these spaces and their meanings, dramatically shifting the field's focus and extending the understanding of the critical importance of this "dark side" of archaeology.