As storms rage in mountain-flanked valleys, the lakes along the Alpine foothills turn into roaring seas. From Bavaria’s Frillensee, Germany’s coldest bathing lake, to the mighty, unfathomably deep Lake Constance, these waters have many faces. Using underwater cameras and a novel subaquatic drone, divers have undertaken countless dives to capture unique images of the lakes’ hitherto unexplored depths. What secrets lie hidden beneath their surface with its ever-changing moods?