It's been 12 years since Grey's Anatomy first premiered. There's been laughter, love, and LOTS of heartache through the years. Here are the most memorable moments from the past 12 years.

20. When Izzy Finds out Denny Dies

This is a heartbreaking moment in Season 2. After so much effort and rule breaking to keep Denny alive, Izzy finds out he died not too long before she showed up.

19. When Meredith Dies - and Comes Back

Meredith flatlines and sees her mom in a dream. Christina and all the other doctors refuse to give up on saving her.

18. When Preston Calls Off the Wedding

Realizing he isn't her first choice, Preston calls off his wedding with Christina. Christina's response was two words - "I'm Free".

17. When We Find Out McDreamy is Married

At the end of season 1, we find out McDreamy is married to a tall redhead named Addison Montgomery. That's when we started hating Addison, because Meredith and Derek are supposed to be together.

16. When Izzy Reveals She Has a Daughter

We thought Izzy's biggest secret was that she was an underwear model. Little did we know that she had a daughter that she gave up for adoption.

15. When Derek Gets Shot

This episode was probably one of the most nerve wracking episodes out there. Bailey gets dragged from under a bed, Meredith revealed she was pregnant to Christina, and Derek gets shot. This is an episode you don't want to miss.

14. When We Find Out John Doe is George

All George wanted to do is go home and spend time with his family after news broke out he enlisted in the Army. He ended up saving someone's life and getting hit by a bus. He was so badly injured no one could tell it was him, until he spelled out "007" in Meredith's palm.

13. When Christina Got Stabbed

Christina walked out of the hospital and was impaled by an icicle. Luckily, Owen Hunt came to the rescue.

12. When the Plane Crash Happened

This episode was a whirlwind of emotions. We started off happy, and ended up heartbroken. We lost Lexi, Mark was injured, and Christina lost her shoe. I mean, seriously Shonda?!

11. When Meredith and Derek Adopt Zola

They were married via Post-It, and finally decided to adopt Zola, and our hearts became full.

10. When April and Jackson Lose Their Baby

After finding out their baby had an fatal illness, they were never the same. I will never get over the episode when they held their baby until he passed.

9. Pick Me, Choose Me, Love Me

Maybe one of the most iconic moments in Grey's Anatomy history. When Addison showed up Meredith tried to fight her feelings for Derek, but her love for Derek couldn't be ignored.

8. When Meredith Was Attacked

Something no one saw coming in Season 12. Meredith was attacked and injured badly. All the doctors worked hard to keep her alive. When Bailey yelled at Maggie to get out because no family could work on her, Alex yells "We're ALL her family." Cue the waterworks.

7. When Jackson Stops April's Wedding

Everyone but Stephanie saw that coming. Jackson and April then run away together. Poor Stephanie.

6. When April Goes Into Labor

When she came home to grab the rings, she goes into labor - to only find out her baby was breech. Ben Warren then had to perform an emergency C-section in the middle of Meredith's kitchen.

5. When We Find Out Jo is Married

We find out Jo is married, and Jo isn't actually her name. We find out she was secretly abused and she can't divorce him, or he will find her.

4. When Amelia Tells Owen She Doesn't Want to Have Kids

Amelia avoids Owen for weeks until she finally informs him she doesn't want to have children - even though that's all Owen wants.

3. When Meredith Finds Out Alex is Home

After searching countless jails for Alex, Meredith finds Alex asleep in her bed... Thank god.

2. When We Find Out Meredith Is Pregnant

Pulling an Ellis Grey (kind of), Meredith moves away after Derek dies. She stays out of contact with everyone, until she answered a call from Alex. Then we find out she is pregnant with her and Derek's third child.

1. When Derek Dies

What did we do to deserve this? All Derek wanted to do was save people's lives. Why does Shonda make us love a character and then kill them off? Derek had a family. We will always miss McDreamy - and the show isn't the same without him.