At the height of its popularity, Glee was inescapable. It dominated prime time television with the same ease it occupied the Billboard Hot 100. A comedy with heart and panache to spare, the misadventures of the groups of misfits earned critical acclaim and an army of faithful fans, for its first couple of seasons at least.

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Out of all 121 episodes in the series, some stand out more than others. Whether because of some major landmark for the characters or, most likely, due to the songs performed, these episodes rank as some of the most memorable of the show, the ones that, no matter how much time passes, will always live in the hearts and minds of Gleeks all over the world.

Pilot

The cast of season one of Glee in a promo image

The episode that started it all, "Pilot" introduces the first season's storylines and clearly establishes the two main characters of the show: Will Schuester, who does lose a lot of prominence over the course of the show, and Rachel Berry, who stays the focus of the story for all six seasons.

"Pilot" also accurately conveys the show's unique comedic style, a fast-paced mix of flashbacks and present action that remained constant until the very end. Add a couple of Sue Sylvester one-liners, one very memorable rendition of "Don't Stop Believin'," and some genuinely funny moments, and this episode is one for the ages.

Duets

Quinn and Sam singing "Lucky"

One of the best episodes of season two, and indeed the entire series, "Duets" makes perfect use of its large ensemble cast to deliver a pleasant and accurate portrayal of high school life and love. When Mr. Schuester assigns the club to perform a duet with another classmate and offers a prize for the winning pair, several relationships grow stronger and some others deteriorate.

"Duets" also serves as Sam Evans' official induction into the Glee club and the beginning of his relationship with Quinn Fabray, as well as the start of Artie and Brittany's. Tina and Mike get the chance to perform a duet together, Mercedes and Santana bring the house down, and Kurt sings a duet by himself. This episode truly has it all.

Journey To Regionals

New Directions performing at Regionals

In the season one finale, "Journey to Regionals," the New Directions compete in Regionals against Aural Intensity and Vocal Adrenaline for the chance to go to Nationals. The ND perform a wonderful medley of Journey that includes Finn and Rachel harmonizing to "Faithfully" and the entire team singing a mash-up of "Lovin', Touchin', Squeezin'," and "Anyway You Want It" before finishing off with a second rendition of "Don't Stop Believin'."

"Journey" also features Jesse St. James's unforgettable rendition of "Bohemian Rhapsody" as Quinn gives birth to her baby. In the end, the New Directions lose but the Glee club gets another year thanks to some meddling from Sue.

Prom Queen

Kurt Hummel gets crowned Prom Queen

One of Glee's most dramatic episodes, "Prom Queen" deals with several simultaneous storylines all taking place on the eve and during McKinley's prom night. Artie tries to win Brittany back after calling her stupid, Finn wrestles with his jealousy at seeing Rachel and Jesse together, Kurt gets a surprise, and Quinn goes out of her way to win prom Queen.

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Like the best episode of the show, "Prom Queen" succeeds because of the excellent use of its amazing cast. Every song is on point and actually serves to further advance the plot. The episode also ends on a cathartic and empowering note that makes this one of the best hours in the show's history.

Props

Sue, Will, Blaine, Rory, and Brittany listening to Tina sing

When it comes to ambitious Glee episodes, none hold a candle to "Props." Based on a completely ludicrous premise, "Props" follows underrated and undervalued character Tina Cohen-Chang as she hits her head and experiences a dream in which she switches places with Rachel.

The sequence also features the entire Glee club switching roles, creating a truly unique and chaotic experience that ranks as one of the most surreal moments in the show. "Props" succeeds thanks to how invested the entire cast is. Particularly noteworthy are Dianna Agron's take on Sugar, the late Cory Monteith doing his best Kurt, and Kevin McHale's impression of Santana.

The Break-Up

Glee's Kurt and Blaine stand on a street at night

An episode that broke the hearts of millions of fans around the world, "The Break-Up" sees Blaine admitting his infidelity to Kurt, leading to their separation. Will and Emma fight about their future, and Santana and Brittany also decide to split in the most mature of ways.

Rachel and Finn have one of the episode's most dramatic moments, though, and they also finalize their romance. The episode features two exceptional numbers, a Rachel/Finn/Kurt/Blaine quartet of No Doubt's "Don't Speak" and a group number featuring all the couples singing their heart out to the tune of Coldplay's iconic song, "The Scientist."

Sectionals

The first mid-season finale sees the New Directions struggling to put a Sectionals setlist together after Sue leaks their original one to their competition. Finn finds out he's not the father of Quinn's baby and Mr. Schuester's rivalry with Sue reaches a tipping point.

"Sectionals" features two of the most memorable numbers in the show's history, with Mercedes and Rachel belting out their trademark songs, "And I Am Telling You I'm Not Going" and "Don't Rain On My Parade" respectively. The episode ends with a contagious rendition of "My Life Would Suck Without You," as Will and Emma share their first kiss.

Nationals

Glee's The New Directions hold a trophy onstage as confetti falls down

After three seasons and countless songs, the New Directions finally become champions in the season three episode, "Nationals." Going against their mortal enemies, Vocal Adrenaline, among several other competitors, McKinley's Glee Club prevails thanks to a setlist that includes Rachel's epic take on Celine Dion's "It's All Coming Back To Me Now," the Troubletones' energetic rendition of Gaga's "Edge of Glory," and an unforgettable version of Meat Loaf's "Paradise by the Dashboard Light" performed as a group number.

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"Nationals" is a cathartic experience, an unforgettable moment that feels earned and earnest at an uncertain time when fans were getting ready to say goodbye to half of the regular cast.

Goodbye

Rachel saying goodbye to Finn and her friends while she boards a train in Glee.

More a series finale than a season finale, "Goodbye" sees Rachel, Finn, Kurt, Quinn, Puck, Mike, and Santana say their farewells (for the time being, at least) to Lima as they prepare to depart for their futures. Rachel is New York-bound, Mike attends ballet school, Quinn goes to Yale, Santana heads to Louisville, Finn and Puck depart to the army, and Kurt remains in Lima.

"Goodbye" plays to Glee's strengths, perfectly mixing emotional moments with admittedly cheesy humor. The result is a heartfelt and genuine hour of television that successfully closes the most successful chapter in the show's history while still hinting at promising things to come. Alas, it was unable to keep that promise, but at least for a while, fans dared to believe.

The Quarterback

The New Directions sing Seasons of Love as a tribute to Finn

Quite possibly the saddest episode in the show, "The Quarterback" is an ode and a tribute to the life of Cory Monteith. Brought to life with delicacy, tenderness, and genuine emotion by the grieving cast, "The Quarterback" deals with the situation as best as it possibly can.

The cast's emotions are so truthful it at times feels as though the audience is intruding in a deeply intimate situation. Yet, the hour feels necessary, a way for fans to say goodbye and mourn an actor whose charm and warmth made their way into millions of people's hearts.

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