Team member Kasia Biernacka looks at an illuminated crystal formation inside Cheve Cave in National Geographic Channel's 'The Deepest Cave.' Director of Photography (DP) and caver Kasia Biernacka is ...

Inside the world’s deepest cave, 7,000 feet below the surface, a sudden flood turns an epic expedition into a desperate fight ...

During the week, Ciara Smart is a PhD candidate in history at the University of Tasmania. On the weekends, she’s a member of a caving club that discovered the deepest cave in Australia over the ...

Why it's incredible: The cave is so deep, the world's tallest building could fit inside it. The Hranice Abyss — or "Hranická propast," in Czech — is the deepest known freshwater cave in the world.

The Hranicka Abyss is at least 1,325 feet deep, and likely goes down further. — -- A team of explorers believe they have discovered the deepest known underwater cavern the world in eastern Czech ...