The Last Unknown

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  1. The Aleutian Islands

  Ian Shive leads a risky expedition into a remote Alaskan wildlife refuge.

• 2. Palmyra Atoll

  Ian explores one of Earth's most well-protected coral reef ecosystems.

• 3. Rose Atoll

  Ian joins a team of scientists to unlock vital new info about coral reefs.

• 4. The Channel Islands

  Ian explores one of America's least-known national parks.

Cast