In 2004, Oprah kicked off Season 19 with a surprise we're still talking about. Relive the infamous car giveaway and watch as Oprah reveals why it's one of her all-time favorite moments.

On November 15, 1988, Oprah kicked off a show called "Diet Dreams Come True" by revealing her new slim figure and demonstrating how much she lost by wheeling 67 pounds of fat onstage in a wagon. It became the highest-rated episode in Oprah Show history. Find out why Oprah sees it as an iconic moment. Plus, does she still have those size 10 Calvin Klein jeans?

Oprah rolling 67 pounds of fat onstage during a 1988 show became the highest-rated episode in Oprah Show history. Where did she get all that fat for the wagon? Plus, Oprah reveals why she shared how she lost the weight at the time.

Many of the world's biggest stars opened up to Oprah about being in love over the years, but none as enthusiastically as Tom Cruise. His display of affection for his then-girlfriend, Katie Holmes, went viral around the world. Find out what Oprah really thought about Tom Cruise jumping on her couch and why she won't show the footage today.

On September 10, 2009, producers pulled off an over-the-top surprise for Oprah with help from tens of thousands of fans and the Black Eyed Peas. Watch as Oprah looks back on the flash mob and see if she agrees that it should be number one on the TV Guide countdown.

Just days after the patriarch of the Osmond family, George Osmond, passed away in November 2007, every member of the extended Osmond family flew to Chicago to reunite on Oprah's stage and honor the legacy George left behind. Watch as Oprah reflects on what that show taught everyone about the importance of family.

Over the years, The Oprah Show's staff prided itself on treating every guest as if they were part of the family. When the entire Osmond family came to Chicago, that family got much bigger. Watch as Oprah reflects on getting all 126 family members, including dozens of children, to Chicago and ready for the show. Plus, meet all the Osmonds!

We're down to the top five! Will your favorite be number one? Watch a sneak preview of the finale of TV Guide Magazine's Top 25 Best Oprah Show Moments.

Of all the incredible stories of survival featured in 25 years of The Oprah Show, TV Guide chose Nate Berkus' harrowing story as the most memorable. On December 26, 2004, a deadly East Asian tsunami killed an estimated 181,000 people. Nate Berkus and his partner, Fernando Bengoechea, were vacationing in Sri Lanka when it hit. Nate survived; Fernando went missing and is presumed dead. On January 17, 2005, Nate shared his story.

Oprah Show designer Nate Berkus and his partner, Fernando Bengoechea, were vacationing in Sri Lanka when a devastating tsunami hit in December 2004. Nate survived; Fernando went missing that day and is presumed to have been killed in the tsunami. Just days after arriving home, Nate shared his story on air. Watch part of that show and find out why Oprah was hesitant to do the interview with this member of the Harpo family.