Blue Realm

Divers test the limits of shark and human interaction with lemon, bull and white sharks; a feeding frenzy of more than 100 reef sharks in the Bahamas.

The remote and barren Socorro Islands offer little refuge to humans, but they are a magnet to migrating fish, whales and large sharks. This program focuses on the archipelago's most intriguing residents, giant manta rays, their unusual behavior and surprising intelligence.

Endangered manatees are killed.