71% of the Earth is covered by water. And most of us imagine it to be a serene, almost silent world. But why should we have all the fun up here? Discover what sound is like just below the surface and all the way down to the ocean's depths. And see how mankind might be making it unpleasant for everyone and everything that calls the oceans home.Featuring underwater acoustician Al Jones, Professor John Hildebrand from the Scripps Institution of Oceanography, and Christophe Haubursin from Vox.com on special assignment.