Sistema Sac Actun is the world’s largest underwater cave system. Stretching an astonishing 215 miles, this submerged labyrinth of tunnels, caverns, and crystal-clear waterways is not only a ...

A group of divers have 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 ...

But there is hope, says Thymann, and documenting this dense habitat of underwater caves may be the first step in protecting the manatees that live there. Receive a weekly dose of discovery in your ...