Dr. Robert Ballard poses with an unmanned submersible, like the one he used when locating and exploring the wreck of the RMS Titanic. A veteran explorer, former U.S. Navy Commander, and professor of oceanography at the University of Rhode Island, Ballard is a giant in deep-sea exploration. But Ballard still loves to get his feet wet, and his idea of a perfect day sees him on his ship, the E/V Nautilus, exploring the 72 percent of our Earth that is covered in water. More about deep ocean exploration can be found in our Deep Ocean Exploration featured story.