Grey's Anatomy: 20 defining moments of its first 10 years

The best thing intern Meredith Grey (Ellen Pompeo) had going for her was her name: After all, being the daughter of the esteemed Ellis Grey (Kate Burton) looks great on paper. And that's what made the realization that Ellis was suffering from Alzheimer's all the more upsetting. Not only was Ellis no longer a great surgeon, but, as we'd later find out, she wasn't a great mother, either. —Samantha Highfill

Grey's Anatomy wouldn't be Grey's Anatomy without its "Mc" nicknames. In season 1, Cristina (Sandra Oh) was the first one to label Derek Shepherd (Patrick Dempsey) "McDreamy." From there, we got McSteamy, McHottie, McVet, McVomit, and so much more. Plus, this episode also contained another Grey's landmark: the first elevator kiss. —S.H.

Meredith and Derek's relationship was filled with drama from the start, but things got even more complicated when his wife, Addison Shepherd (Kate Walsh), greeted the new couple at the hospital. Meredith didn't know Derek was married until that very awkward moment, and Derek didn't know Addison was coming to visit, so it was an unfortunate surprise all around. Although Addison first came off as a villainous, Cruella de Vil type of character, she went on to become one of the show's strongest players — and even earned herself a spin-off in the process. —Ariana Bacle

Cristina told Meredith she put her name down as her emergency contact by saying, "You're my person." From that moment on, the relationship between these dark-and-twisty individuals was unbreakable — even when they went on to have an episodes-long argument in a later season — and became a model for positive depictions of female friendships in pop culture. —A.B.

When Addison first showed up in Seattle, Meredith tried to fight her feelings for Derek — considering he was, you know, a married man. But as the season started to unfold, Meredith realized that her love for Derek couldn't be ignored, and everything came to a head in one of the show's most memorable moments. Not only did it demonstrate Shonda Rhimes' ability to write one hell of a romantic speech, but, within the show's universe, it also let Derek know that Meredith was still an option. —S.H.

This two-parter demonstrated just how great the show could be, and also set many things in motion: George (T.R. Knight) helped Bailey (Chandra Wilson) give birth to her son, Alex (Justin Chambers) and Izzie (Katherine Heigl) slept together, Cristina realized the extent of her feelings for Burke (Isaiah Washington), and Derek was forced to imagine a life without Meredith. (And he didn't like it.) —S.H.

Izzie tried to save Denny's (Jeffrey Dean Morgan) life by cutting his LVAD wire, which stopped his heart — and hypothetically put him higher on the list for an immediate heart transplant. Her plan worked, but he later died anyway from a stroke. Izzie ended up unraveling, quitting her job at the hospital (but eventually returning to open up a free clinic using the millions of dollars Denny left to her). —A.B.

First and foremost, the ferry crash was symbolic of Meredith's state of mind — just seasons earlier, Derek had talked about his love of Mer as his love of "ferryboats." Add to that the fact that Meredith's drowning set off a number of changes: From McSteamy (Eric Dane) and McDreamy finally acting like friends to Derek questioning whether Mer drowned on purpose, multiple relationships would never be the same. And for Meredith, her time in limbo allowed her to say goodbye to her mother, who finally told her daughter that she was "anything but ordinary." With that, Meredith woke up. Ellis didn't. —S.H.

Burke and Cristina were so close to getting married — so close! — but Burke backed out at the very last minute after realizing he didn't want to marry Cristina as she was: He wanted Cristina to be a different woman completely, and it was best for both of them for him to let her go. With that, Burke was gone from the show (until a brief appearance in season 10), and Cristina was left heartbroken. —A.B.

Derek loved Meredith even when she was dark and twisty, but their relationship was never going to work until she dealt with some of the things in her past. It wasn't until Meredith went to therapy that she was finally able to go to Derek, create a house of candles, and tell him that she was "whole and healed" and ready to be together forever. —S.H.

Spoiler: When your dead fiancé shows up and the two of you engage in some ghost sex, it's probably because something's not right in your head. And for Izzie, it all stemmed from a brain tumor. The moment she figured that out, her life changed...as did the show. —S.H.

Serving as a trauma surgeon for the U.S. Army can negatively affect the mental health of anyone, Owen (Kevin McKidd) included. The extent of his PTSD was revealed when he strangled Cristina in his sleep one night, resulting in their (temporary) breakup and showing that even those with the toughest of exteriors — Owen is the same guy who stabbed a bunch of pigs just so his employees could operate on them — might be hiding unimaginable struggles. —A.B.

With Izzie's illness, George's decision to join the army, and a very injured John Doe in the hospital, Meredith and Derek's wedding was seeming more and more unlikely. So when a frustrated Meredith couldn't find the time, Derek came up with a solution: They'd write their vows on a Post-it note, sign it, and then he'd kiss the bride. The couple then promised to love each other (even when they hate each other), and to never run — among other things. Eventually, they'd have to head to City Hall so that they could adopt Zola, but, as far as they were concerned, that Post-it note represented their marriage...and that's why it hung above their bed. —S.H.

An unrecognizable patient was admitted to the hospital after getting hit by a bus. It turned out to be George, who revealed his identity by using his fingers to write "007" — the nickname Karev gave him way back when — in Meredith's palm. This revelation was all the more shocking because Izzie, deep into her cancer struggle, was also on the brink of death. She ended up making it; George did not. Out of all the many, many Grey's deaths, George's continues to hit the hardest — both because of how shocking it was and because, up until then, George was really the heart of the show. —A.B.

After introducing a number of new characters via a hospital merger, Grey's seemed to recognize its mistake: In the season 6 finale, a number of those new faces were killed by a gunman. Along with getting rid of the less-loved characters, the shooting also nearly took down Derek (and made standing in an operating room an impossibility for Cristina). —S.H.

While Arizona (Jessica Capshaw) was off in Malawi, Callie (Sara Ramírez) had sex with Mark — and got pregnant with his baby. Then, Arizona came back to the U.S. early for Callie, and was welcomed with the news that — surprise! — her ex-girlfriend was pregnant with someone else's child. This baby would go on to bond Callie and Mark together forever, even after his death in season 9, and create both obstacles and plenty of joy for first-time moms Callie and Arizona. —A.B.

Knowing that robot Cristina was the best heart surgeon in the hospital, Teddy (Kim Raver) asked Owen and company to trick Cristina into operating on her husband. But even the robot couldn't save Henry (Scott Foley). It was a loss that would change Teddy forever, and an operation that would change Cristina — once she found out the identity of her patient. —S.H.

As if life weren't already hard enough for the people of Seattle Grace Mercy West, a few of them got in a plane crash that left Lexie (Chyler Leigh) and Mark dead, and Arizona so injured that Callie eventually had to make the call to amputate her leg. The deaths, the amputation, and the crash itself caused serious consequences that left the survivors — Derek, Cristina, Meredith, and Arizona — reeling in their own (occasionally destructive) ways. And the aftermath didn't just last for a season: Callie's decision to amputate Arizona's leg came up again in future seasons, and became one of the main reasons why their relationship was a rocky one. —A.B.

In a way, Webber (James Pickens Jr.) had lost Adele (Loretta Devine) already, after she started to show signs of Alzheimer's and eventually found a new boyfriend in her assisted living facility. But that didn't make her death any easier for him: She met her end right before Bailey's wedding, where Webber told Meredith (but not Bailey) the truth about Adele's passing. Then, as Bailey and Ben (Jason George) swayed through their first dance, he daydreamed he and Adele were in their place. Even though Adele was just a supporting character, she played a huge role in the show from the beginning. Her death signified an era — in both the show's and Webber's life — coming to a close. —A.B.

Cristina leaving for Zurich wasn't just important for her character's development, but for Meredith's: She leaves Grey by saying, "[Derek's] very dreamy, but he's not the sun. You are." Those words have stayed with Meredith throughout the series, making an obvious effort to focus on herself and her own success. —A.B.