Mexican scientists discovered the world’s largest flooded cave system that extends an amazing 216 miles (347 km) and is filled with artifacts. The maze of caves is a major archaeological find that promises to shed light on the mysteries of the Mayan civilization. The discovery of the cave system, known as Balamku or “Jaguar God,” was announced by Mexico’s National Institute of Anthropology and History (INAH) in a press conference held today in Mexico City. After its initial discovery by farmers in 1966, Balamku was visited by archaeologist Víctor Segovia Pinto, who wrote up a report noting the presence of an extensive amount of archaeological material. But instead of excavating the site, Segovia then directed the farmers to seal up the entrance, and all records of the discovery of the cave seemed to vanish. Unveiling their preliminary findings this week, a research team led by underwater archaeologist Guillermo de Anda from Mexico’s National Institute of Anthropology and History said the sprawling cave consists of almost 250 cenotes (naturally occurring sinkholes) and hosts 198 archaeological sites, some 140 of which are Maya in origin. “This undoubtedly makes it the most important submerged archaeological site in the world,” de Anda says. “Another important feature is the amount of archaeological elements that are there and the level of preservation they contain.” Among the finds the divers have already uncovered are human remains, including skeletons and seemingly burnt human bones, that are at least 9,000 years old – suggesting human activity in the eastern Mexican region goes back thousands of years earlier than researchers thought, possibly as part of an ancient Maya trade route. “The merchants followed established routes and used these places as ritual pilgrimage points, they made stops at altars and sacred sites to make an exchange with the gods and they’ve left their mark there,” de Anda told media at a press conference. De Anda, who leads the Great Maya Aquifer Project (GAM), suggests people probably didn’t actually live in the branching underwater cave – called the Sac Actun System – but ventured inside it during periods of great climate stress to search for water.