Hidden cameras reveal how teens react to different bullying situations.

Watch amazing animals and the true stories behind some of the most popular videos on the web.

A successful young man is shot down in front of his Philadelphia home. A woman finds her way back to her family after being kidnapped 30 years earlier.

Brian Williams documents a day behind-the-scenes on Capitol Hill where viewers will get an unprecedented look at life under the U.S. Capitol dome.

A couple's romantic night at the Hudson Palisades ends in a tragic fall, leaving officials questioning whether or not it was an accident.

A young woman teams with a U.S. Marshal to find the man who murdered her mother 18 years earlier.

A young detective investigates a college student's death; chronicling the events of the Casey Anthony murder trial.

The impact of the recent tornadoes, severe thunderstorms and flash-flood warnings in the United States; reports from London include behind-the-scenes coverage of the royal wedding.

Chris Hansen goes under cover with California lottery investigators; testing the integrity of lottery clerks in New York.

NBC’s Dennis Murphy traces the journey of Kate Middleton from commoner to Her Royal Highness.

The citizens of a Wisconsin town come together to renovate a family's home.

A serial killer stalks human prey through America's national forests until clues help trigger a multi-state manhunt.

Also: a look at actor Charlie Sheen's home life at his estate. Correspondents: Keith Morrison and Jeff Rossen.

Dennis Murphy investigates the mysteries surrounding the shooting deaths of two family members in a still Georgia hamlet.

A doctor disappears while on vacation with his wife, leaving her $6 million in debt.

Chris Hansen visits a shop in New York that sells bath salts, a new designer drug.

A young father fights desperately across the United States for custody of his baby girl. Plus the story of Nancy Cooper who went missing while jogging in a suburb of Raleigh, North Carolina.

A man who was arrested and tried three times for the death of his wife of four months talks about the case.

Keith Morrison reports the story of an Oklahoma pastor's son and daughter who endure a remarkable road to recovery after witnessing a terrible family tragedy.

A former homecoming queen comes under suspicion after her husband is found stabbed to death and an affair with the local youth pastor is uncovered.

Richard Engel reports on the Battle of Wanat, one of the worst casualty counts of the Afghanistan war that left nine soldiers dead and 27 injured the families of one platoon come together to grieve and uncover why their sons died.

When a 38-foot empty Donzi boat is found making circles in the ocean with nobody on board, a mystery begins in the Bahamas. While hundreds of Americans die every year from accidental carbon monoxide, NBC News’ Kate Snow previews one case that police say was not an accident, but potential murder.

Lester Holt takes viewers into Chicago communities, children who grow up quickly and die young.

Correspondent Hoda Kotb delves into a four-year international custody battle.

When Amber Dubois vanished in San Diego County, a search turned up nothing. Then, a year later, Chelsea King disappeared in a neighboring town. Tonight, Keith Morrison reports on the mystery of the missing California teens.