Though explorers have been searching Earth's deepest waters for many years, experts estimate that we have explored only about five percent of the global ocean.

Readers (Grades 3-5) will learn about the history of deep-sea exploration, from the creation of the earliest submersibles to today's high-tech expeditions to the planet's deepest points. They will also find out what we've discovered underwater so far and what lies in store for the future of deep-sea exploration.