Standing on a beach looking out to sea leads many of us to ponder the question, The explorers among us grab a mask and snorkel to see for ourselves. Warm, sunny waters invite hands-on exploration, making for enjoyable vacations. But what about the vast majority of the oceans deeper than 40 meters (131 feet)—beyond the range of most scuba divers? Technological advances, often driven by the military and the oil industry, have given scientists new tools to take them deeper. As a result, ocean exploration has increasingly
