Nature and EnvironmentDon't underestimate our underwater worldTo view this video please enable JavaScript, and consider upgrading to a web browser that supports HTML5 videoNature and Environment05/23/2018May 23, 2018Cave diving may sound like an extreme sport, but Jill Heinerth doesn't explore underwater caves for the adrenaline kick - she wants to reveal hidden clues to the health of our environment and its history.https://p.dw.com/p/2y8DnAdvertisement