Sistema Sac Actun – Mexico (18/20)

Located in the Yucatán Peninsula, Sistema Sac Actun is the longest cave system in the world, stretching over 378 kilometers (235 miles). This vast labyrinth of underwater and dry passageways has been a source of fascination for cave divers. Researchers believe the system is part of a larger network of caves once used by the ancient Maya civilization. Adventurers and divers venture into the depths to discover freshwater pools, stalactites, and remnants of ancient rituals.