Sitting on top of one of the world’s largest super-volcanos are 3,500 square miles of the most spectacular American wilderness. This summer, National Geographic Channel opens this world to you LIVE with a four-night special event. The action reaches boiling point in the world’s first National Park, Yellowstone.

In the criminal justice system, sexually-based offenses are considered especially heinous. In New York City, the dedicated detectives who investigate these vicious felonies are members of an elite squad known as the Special Victims Unit. These are their stories.