Many of us have seen those terrain shaded maps which show the variable terrain above ground - but what about our "blue planet"? NOAA have created this KML which allows you to explore bathymetric (the study of water depth) data for many of America's esturies. To view, click on the placemark description bubble and open the top option "View Bathymetry". This will load an image overlay of the data captured, using a shaded relief scale. This kind of use is beneficial for many scientific studies - from erosion to navigation.