America's National Parks at 100

The National Park Service has been active for over a century preserving and protecting over 400 units across America, from the wild and natural to the man-made and historic. Take a tour through iconic Yellowstone and the Grand Canyon and discover smaller, hidden treasures throughout the country.

Yellowstone National Park is home to a vast array of landscapes and a huge diversity of animals, united in a fascinating ecosystem, one that is currently in severe trouble. The area once contained over 19,000 elk, but its numbers have plummeted by 80% in the last two decades. The mysterious decline has sparked many questions, and researchers are in a race to provide answers. Join them as they investigate a series of theories and suspects, from wolves to bears to trees to trout, in an attempt to solve this alarming puzzle.