In 1990, a woman named Truddi Chase appeared on The Oprah Show to discuss the brutal sexual assault she suffered as a child and how she coped with that pain by splitting into 92 different personalities. Her story encouraged countless other survivors to break their own silence about sexual abuse, including Oprah. Watch as Oprah describes why she was so overwhelmed by the interview.

In 25 years, Oprah interviewed hundreds of survivors of sexual abuse but says Mackenzie Phillips' story struck a very strong chord with viewers. Watch as Oprah reflects on the response she received after Mackenzie told her story on The Oprah Show.

Of all the confessions in the Oprah Show vault, TV Guide Magazine picked this as the ultimate shocker. Watch as Oprah reflects on Mackenzie Phillips' revelation of the sexual abuse she suffered from her father, singer John Phillips.

It's the "out-of-body moment" that sent Oprah into the ugly cry. Watch as she looks back on being surprised onstage by her all-time favorite teacher, Mrs. Duncan!

Oprah says she's always kept a small circle of trusted advisers. During his short life, Oprah says, Mattie Stepanek was one of her most trusted confidants. Watch as Oprah remembers Mattie's light and reads the poem he shared on his first Oprah Show appearance.

Poet and peacemaker Mattie Stepanek wasn't just an Oprah Show guest. He was a friend and trusted personal advisor to Oprah. Watch as she recalls his counsel on a decision that changed the entire trajectory of The Oprah Show.

Back in 2004, Oprah introduced the world to an extraordinary little boy, poet and peacemaker Mattie Stepanek. The 11-year-old, who was wise beyond his years, became an Oprah Show regular and one of Oprah's favorite guests. Watch as Oprah reflects on their first meeting.

TV Guide Magazine is counting down the most famous and memorable moments on The Oprah Winfrey Show! Featuring new commentary by Oprah Winfrey and an interview with TV Guide editor-in-chief Debra Birnbaum, the series revisits the most unforgettable interviews, guests, performances and occurrences of the history-making show.