Awesome Imagery...

Sonar has come a long, long way since the primitive gear I worked with in the Navy some 40 years ago.  Back then, state of the art was detecting the existence of a submarine, or the depth of the water under the ship.  These days, side-scanning synthetic-aperture sonars take “pictures” that look like sharply focused old-fashioned black-and-white photos:

This shows the stern of the Titanic (at left) and many piece of debris from the ship after in broke in two on the way down.  It's not a simple sonar image, but rather a composite painstakingly made using a combination of sonar imagery and underwater photography.  I like the relief provided by the shadows; it makes the image “pop” almost as though it were 3D.

Much more here...