An immersive journey to witness a natural wonder—the underwater caves and cenotes of Mexico’s Yucatán Peninsula, a destination very few divers have ever reached. Shining a light on the Underworld (or Xibalba, as the Mayans called the center of their culture and mythology), these stunning images transport us into a place that few cave divers can reach—a world accessed from cenotes, water-filled gateways to labyrinths of tunnels that create the longest underwater cave systems on the planet. Over several years and multiple diving expeditions, Martin Broen has captured more than 250 different cenotes and caves, diving through mazes of pitch-dark tunnels. Paired with images of startling otherworldly beauty, his engaging text guides readers through the depths of the mysterious Yucatán cenotes—from their formation and spectacular features to their time capsules of ancient fossils, from how cenotes were a source of life for ancient peoples to their critical environmental role today. With contributions based on their own experiences in cenotes by Alex Mustard and Paul Nicklen, this volume beckons divers, cavers, and armchair explorers to explore a uniquely dangerous yet beautiful and essential underwater world.