The Census of Marine Life, a decade-long project encompassing more than 2,700 scientists across the world, sought to answer a basic but daunting question: What lives in the ocean?
The census revealed thousands of new species. National Geographic's new book "Citizens of the Sea", captures many of them.
A closeup of the eye of a sperm whale (Physeter macrocephalus). These whales were prized for a waxy material used in candles, soaps and cosmetics.
This image is from National Geographic's new book "Citizens of the Sea."