Beneath the surface of the Southern Ocean, vast volumes of cold, dense water plunge off the Antarctic continental shelf, cascading down underwater cliffs to the ocean floor thousands of meters below.

For "Earth Day", the National Geographic documentary series "The Secret World of Penguins", produced by Oscar winner James ...

Welcome to Nat Geo Your Shot: National Geographic’s global community for aspiring visual storytellers. Find the community on Instagram @NatGeoYourShot and follow along for hashtag challenges ...