A group of divers has connected two underwater caverns in eastern Mexico to reveal what is believed to be the biggest flooded cave on the planet, a discovery that could help shed new light on the ancient Maya civilization.
The Gran Acuifero Maya (GAM), a project dedicated to the study and preservation of the subterranean waters of the Yucatan peninsula, said the 347-km (216-mile) cave was identified after months of exploring a maze of underwater channels.
Near the beach resort of Tulum, the group found that the cave system known as Sac Actun, once measured at 263 km . . .