Sistema Sac Actun is the world’s largest underwater cave system ... Sistema Sac Actun is part of the region’s vast network of cenotes. They were revered by the ancient Maya as sacred portals ...

The World's Largest Underwater Cave in Mexico is Filled With Ancient Mayan Treasures, Baffles Experts Explorers as a part of ...

The Sistema Sac Actun is the world’s longest underground river system ... and sinkholes, or cenotes, which have long been sources of fresh water and spiritual sites for the Maya people.