The oceans today are the last refuge of giant animals that evolved and thrived for eons on planet Earth. From sperm whales to great white sharks, these creatures have long inspired fear and awe. Thanks to advances in investigative techniques and camera technology, we can now enter their lives to glimpse their social rituals, sensory capabilities, and sophisticated survival strategies. Photography by some of the world's best cinematographers, including Shark Week superstar Andy Casagrande.