Image Source: ABC [1]

The 300th episode [2] of Grey's Anatomy [3] is a love letter to the show in moving pictures, packed with allusions to its early episodes and tributes to past characters. It's truly a nostalgic treasure trove for Grey's fans who have endured 14 dramatic, sexy [4], and heartbreaking [5] seasons. After drying our eyes, we've marked down the most important throwback moments in this stroll down memory lane. Spoilers ahead, of course.

1. Meredith chats with Alex about the Harper Avery Award during a ferry boat ride.

If you recall, Meredith's late husband, Derek [6], has a love for ferry boats that starts when he first moves to Seattle. In the very second episode of the series, he gushes to Meredith about his love for them. Just before his death, he records his very last voicemail [7] to Meredith while on a ferry boat ride.

2. The new batch of interns slump against a wall in some obscure part of the hospital, groaning about how tired they are.

This is also a throwback to the second episode of the first season, during which we see the original interns (Meredith, Alex, Izzie, George, and Cristina) moping together. They feel helpless about not knowing anything about medical surgery. Even if you're not a hardcore Grey's Anatomy [8] fan, you may have seen the infamous GIF of this moment lurking around the Internet.

Image Source: ABC [9]

3. Two county fair victims, Cleo and Greg (aka look-alike Cristina and George), shock Meredith with their uncanny similarities to her friends.

Cleo and Greg are Cristina and George doppelgängers, from the way they look to the way they act — Cleo, blunt and ambitious, and Greg, sweet and a little dopey. They're transported to the hospital still stuck together in roller-coaster seats. This particular image is reminiscent of the simultaneously impaled train crash victims, Bonnie and Tom, from way back in season two. In the episode, the surgeons deem Bonnie a lost cause, while Cleo insists that Meredith saves her life. Cleo's strong will might be a nod to Meredith's recent transformation [10] into a more focused, innovative surgeon a la Cristina.

4. After noticing clone Cristina and George, Meredith sees a very pregnant Izzie look-alike.

Liza is very much like Izzie Stevens [11]. She's perky and always smiling — even Alex is a little shaken by how similar she is to his ex-wife. There's also something to be said about her pregnancy. Back in season three, Alex befriends and begins a relationship with patient Rebecca Pope, a pregnant woman who loses her memory during a massive ferry accident. Liza may represent the ghosts of Alex's past and of the relationships that turn him from an immature frat boy into an emotionally responsible man.

Image Source: ABC [12]

5. After many, many seasons, the show finally uses Psapp's "Cosy in the Rocket," leaving die-hard fans squealing with nostalgic glee.

Cleo says she's going to kill Liza for suggesting they go on the roller coaster. To which Liza, rebuffed, says "Seriously?" (which is classic Grey's vernacular, by the way). Then, Psapp's electro bop "Cosy in the Rocket" starts playing, and the scene fades into the sexy (but retired) Grey's Anatomy intro montage.

6. A tear-stricken Dr. Bailey hears a strange noise coming from the skills lab. It's DeLuca and the new intern Sam, who have been making out.

OK, so this moment has nothing to do with the original cast, but making out and hooking up [13] in on-call rooms and other discreet places in the hospital is such a Grey's Anatomy trope. The whole making out in secret hospital rooms started with Cristina and Burke way back in season one. Since then, we've lost track of how many makeout sessions there have been in the little nooks and crannies of Grey Sloan.

Image Source: ABC [14]

7. As a ballad cover of Ingrid Michaelson's "Keep Breathing" plays in the background, Webber and Bailey operate on Greg while Arizona and Alex deliver Liza's baby.

This moment nods at that gut-wrenching scene in the season five finale when Izzie flatlines and the staff learn that John Doe is actually George. Except this time, the doctors pull off a miracle, and everyone survives. Fans will also remember "Keep Breathing" as the song that plays when Burke leaves Cristina at the altar in season three.

8. Alex tells Jo what he thinks Izzie is doing right now: she has three children, lives somewhere woodsy, and refuses to let her husband take down the Christmas decorations.

Long before Jo's arrival, Alex and Izzie seemed to be the other meant-to-be couple in Grey's Anatomy besides Meredith and Derek. Their history together runs deep. In the season two episode called "Grandma Got Ran Over By a Reindeer," we learn about Izzie's love for Christmas. It's also the episode when Alex and Izzie first awkwardly reconcile after he breaks her heart by sleeping with a nurse.

Image Source: ABC [15]

9. Meredith learns that she has won the Harper Avery Award. In the hospital crowd cheering for her, she sees her late mother.

After years and years of hard work [16], Meredith finally and gloriously wins the prestigious Harper Avery Award. In seasons one to three, we see Meredith emotionally tormented and slighted by her illustrious mother Ellis Grey, who herself has won the Harper Avery twice. It's rare to see Ellis approving of her daughter, though we do get slivers in Mer's hallucinations, like when she tells Meredith that she is anything but ordinary [17] in the season three episode in which Meredith almost dies.

10. After a long day at work, Meredith and Alex call Cristina and drink Champagne from paper cups.

The showrunners introduce us to Meredith's love for tequila when Izzie throws a huge party in season one. Champagne is no tequila (Cristina and Meredith's drink of choice), but the doctors at Grey Sloan are always game for a drink whether it's to celebrate or wrap up a bad day. Also, it's no coincidence that all the drama happens at the bar Joe's. In fact, that's where Meredith and Derek first meet before their one-night stand.

It's hard to process the nostalgic punch of this episode, but we should savor the bittersweet feeling before Grey's Anatomy hits us with another heartache [18].