World's largest underwater cave discovered in depths of Mexico

A team of underwater explorers claims to have discovered the world's largest flooded cave in Mexico.

After 10 months of exploring the watery, underwater passageways of the Great Maya Aquifer, a team of divers achieved a major breakthrough this month when they found an open tunnel linking two of the world's largest flooded cave systems.

Between caves Sac Actun, and Dos Ojos in Tulu, Quintana Roo, the underwater cave measures 347 km in length -- or three times as long as the English Channel.

According to the rules of caving, when two cave systems are connected, the largest cave absorbs the smallest. That means Dos Ojos will now be referred to by its bigger sibling, Sac Actun, explains the group Great Maya Aquifer Project (GAM), leading the mission.

In Mayan lore, the underwater caves were considered a sacred entrance to the Mayan underworld.

Dramatic footage captured with GoPro cameras reveal bones, intact pottery, and stone carvings lying in a watery grave.

"This immense cave represents the most important submerged archeological site in the world, as it has more than a hundred archeological contexts, among which are evidence of the first settlers of America, as well as extinct fauna and, of course, the Mayan culture,"said Guillermo de Anda, researcher at the National Institute of Anthropology and History and director of the Great Maya Aquifer, in a statement.

Along with being an archeological marvel, explorers note the cave's importance as a large reserve of freshwater for the area's biodiversity.

While the GAM began aggressively looking for the connecting passageway since last spring, the discovery marks a major milestone for exploration director Robert Schmittner, who has been chasing after the link over the last 14 years.

The team says their next goal is to search for connections between Sac Actun and three other underwater cave systems.

Scientists will also analyze the water quality, local biodiversity, and study the cave's archeological context.

Watch footage of the exploration at https://youtu.be/dgqgKynzE7o.