WARNING: The following article contains spoilers for Avengers: Endgame, in theaters now.
The culmination of the Marvel Cinematic Universe's Infinity Saga, told across 22 films over the past 11 years, Avengers: Endgame is packed with references and Easter eggs to the entire history of the blockbuster franchise, as the surviving heroes travel through time and space to recover the Infinity Stones and restore their fallen friends.
Here are the best nods and callbacks to previous MCU films, excluding the obviously overt return to major settings -- the Battle of New York from 2012's The Avengers, for instance -- and appearances by characters long dead, brought back through the wonders of time travel.
Civil War Revisited
One of the first people to greet Tony Stark as he arrives back on Earth, courtesy of a timely rescue by Captain Marvel, is his frenemy Captain America. The two had been estranged since coming to blows in Captain America: Civil War, and, as Tony recovers from weeks of malnutrition after being stranded in deep space, Iron Man airs his grievances against Steve Rogers for not being there when he was needed most during Avengers: Infinity War.
Over the course of his tirade, the emaciated Tony makes overt references to both Steve's letter promising his continued support at the end of Civil War and his own prophetic vision during Avengers: Age of Ultron. Reminding the present heroes he was attempting to "build a suit of armor around the world" to protect it from Thanos, Tony directly quotes the circumstances that led to his fracture with Captain America.
A Familiar Norwegian Town
As the Avengers regroup five years after the death of Thanos with a new strategy to recover the Infinity Stones that involves time travel, Hulk travels to Tønsberg, Norway, to recruit Thor, and also reunites with Valkyrie, Korg, and Miek. The real-life fishing village has since become New Asgard, Thor having taken his father's advice in Ragnarok to create a safe haven for Asgardian refugees in Norway.
The town actually has a lengthy history in the MCU, stretching back for ages as the location where the Frost Giants led by Laufey invaded Earth, only to be repelled by Odin as seen in the prologue to 2011's Thor. The village is attacked by Red Skull and Hydra at the beginning of Captain America: The First Avenger, in which the villain recovers the Tesseract, which had been hidden there for centuries.
Awkward Elevator Ride
While traveling back to the Battle of New York from 2012's The Avengers, it's revealed how Hydra obtained Loki's scepter, housing the Mind Stone, as seen in the mid-credits scene to Captain America: The Winter Soldier. Hydra operatives Brock Rumlow and Jasper Sitwell, while still undercover as S.H.I.E.L.D. agents, take the scepter with them in the aftermath, while Robert Redford's Alexander Pierce unsuccessfully attempts to obtain the Tesseract from Thor before he returns with Loki to Asgard.
Tasked with recovering the Mind Stone, Captain America boards the elevator with Rumlow and Sitwell to take back the scepter in a tense sequence that's a shot-for-shot callback to the iconic elevator fight from The Winter Soldier, the first MCU scene ever filmed by directors Joe and Anthony Russo, right down to camera angles and the positioning of the actors. Ultimately, Captain America deceives the Hydra agents into thinking he's one of them by whispering "Hail Hydra," and makes off with the scepter.
"I Can Do This All Day"
Captain America's mission takes an unexpected turn when he finds himself face to face with the 2012 version of himself as he tries to leave Stark Tower with the scepter. Confusing the doppelganger for Loki, who had tauntingly transformed into Captain America -- itself a callback to Thor: The Dark World -- the two Sentinels of Liberty fight.
As the brawl begins, the 2012 Captain America remarks that he "can do this all day." The quote is one first made by an unpowered Steve Rogers confronting a bully outside a theater during The First Avenger. Cap later echoes the same quote after he endures a beating from Iron Man in Civil War. Hearing himself make the declaration for the third time in Endgame, the present-day Steve Rogers is understandably nonplussed.
Worthy of Mjolnir
Learning of the fully powered Infinity Gauntlet's location in the future on Earth, Thanos travels through time himself and attacks the New Avengers Facility in Upstate New York. As Hawkeye attempts to keep the Gauntlet away from Thanos' forces, Captain America, Iron Man and Thor buy him time by taking the fight to the Mad Titan. As Thanos prepares to execute an out-of-shape Thor, the 2013 version of Mjolnir recovered by the god of thunder during his visit to the events of The Dark World is taken up in a pivotal moment by Captain America.
The idea of Captain America being worthy enough to wield Mjolnir has been explored in comics for decades. In the MCU, the concept was teased in Age of Ultron, with Thor challenging his fellow Avengers to lift the hammer after a party in Avengers Tower. Of all the Avengers, Cap is able to actually make the hammer move, much to Thor's surprise. Now, in his moment of need, Captain America is truly worthy to wield the enchanted hammer, with an ecstatic Thor exclaiming he "knew it."
"On Your Left"
As Thanos assembles his army to attack the Avengers, Captain America braces himself for his impending death. Just before the charge, Cap receives a surprise comm call from a newly resurrected Falcon informing to expect reinforcements "on your left," just before all of the returned heroes, including Wakandans, Masters of the Mystic Arts and Asgardians, teleport to the battlefield.
"On your left" are the first words Steve Rogers ever spoke to Sam Wilson, at the beginning of The Winter Soldier, as he passed him multiple times while the two were jogging on the National Mall in Washington, D.C. Now back in action, it's a nice callback to the friendship between the two as Falcon returns when he's needed the most.
Captain America's Nickname
Back in the fight, Ant-Man finds himself reunited with his Hope Van Dyne, the Wasp. Resurrected following the mid-credits scene of Ant-Man and the Wasp, Hope is understandably perplexed when she first enters the battle, but quickly acclimates and observes that Cap needs them as the conflict intensifies.
In Ant-Man and the Wasp, Scott Lang referred to Captain America as "Cap" when discussing their team-up during Civil War, with Hope amused by the nickname. After using the diminutive herself in Endgame, Scott flashes Hope a knowing smile before the two leap back into action.
Famous Last Words, and a Familiar Handshake
Now back among the living, Peter Parker watches his mentor Tony Stark die after using the Stark Gauntlet to disintegrate Thanos and his army with one final declaration of "I am Iron Man." A heartbroken Peter returns to his high school in Queens, where he's reunited with best friend Ned Leeds, and the two exchange a multi-stage handshake.
Tony's final words in the MCU are also his last words in 2008's Iron Man as he eschews a cover story provided to him by S.H.I.E.L.D., and instead reveals his alter ego to the world at a press conference. Peter and Ned's subsequent somber handshake is the same one used by the two multiple times, under happier circumstances, in Spider-Man: Homecoming.
The Funeral of Tony Stark
After everyone returns to their normal lives, the Avengers mourn Tony Stark's death in a lakeside funeral by his home with Pepper Potts and their daughter Morgan, named after an eccentric uncle, as mentioned by Tony during Infinity War. The ceremony is a veritable who's who of the MCU, with attendees paying their respects as Pepper releases a wreath onto the lake.
Housed within the arrangement is Tony's first arc reactor, which he used to power the Mark I and escape his captors in Afghanistan in the 2008 film. Pepper later gifted it to him. Also, among the attendees is a silent teenager, Harley Keener, who helped Tony over the course of Iron Man 3. Finally, after the funeral, Morgan tells Happy Hogan she would like cheeseburgers, which he observes her father was fond of too, as seen in the original Iron Man.
The Final Fate of Captain America
Endgame also reveals the final fate of Steve Rogers, tasked with traveling back in time through the Quantum Realm to return all six Infinity Stones and Mjolnir to their proper places to avoid causing any reality-threatening paradoxes. Steve bids farewell to Bruce Banner, Sam Wilson and Bucky Barnes to complete his mission, but remains in the past to live out his life, marrying Peggy Carter and finally getting that promised dance.
Steve and Bucky's farewell echoes their final conversation, line for line, in The First Avenger before Bucky was deployed to fight in World War II. The final scene of Steve and Peggy dancing in their home, presumably in the late 1940s, makes good on their promise to share a dance after the conclusion of the war, interrupted by Captain America crashing a Hydra plane before it could destroy New York. The couple quietly dance in their living room to the same song played by Nick Fury in Steve's apartment in The Winter Soldier to mask their conversation from Hydra.
Directed by Joe and Anthony Russo, Avengers: Endgame stars Robert Downey Jr. as Iron Man, Chris Evans as Captain America, Mark Ruffalo as Bruce Banner, Chris Hemsworth as Thor, Scarlett Johansson as Black Widow, Jeremy Renner as Hawkeye, Brie Larson as Captain Marvel, Paul Rudd as Ant-Man, Don Cheadle as War Machine, Karen Gillan as Nebula, Danai Gurira as Okoye and Bradley Cooper as Rocket, with Gwyneth Paltrow Pepper Potts, Jon Favreau as Happy Hogan, Benedict Wong as Wong, Tessa Thompson as Valkyrie and Josh Brolin as Thanos. The film is in theaters now.