Please te that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Caves are underground spaces that can be explored. Diverse in their origins and specific ecosystems, caves include those formed through limestone, primary lava caves, sea, glacier, and others. This book sees through the darkness of caves, exploring the types, the study called speleology, cave conservancy, plus the cave-related hobbies and sports like spelunking, cave diving, mine exploration, and more. Project Webster represents a new publishing paradigm, allowing disparate content sources to be curated into cohesive, relevant, and informative books. To date, this content has been curated from Wikipedia articles and images under Creative Commons licensing, although as Project Webster continues to increase in scope and dimension, more licensed and public domain content is being added. We believe books such as this represent a new and exciting lexicon in the sharing of human kwledge.