Explorers discover the world's deepest underwater cave in the Czech Republic, with the limestone abyss measuring at least 404 metres deep.
from Top Stories http://ift.tt/2cJwKNh's-deepest-underwater-cave-hranicka-propast-discovered/7896218
Explorers discover the world's deepest underwater cave in the Czech Republic, with the limestone abyss measuring at least 404 metres deep.