MCU fans are feeling nostalgic after reliving the action-packed first trailer for the beloved Avengers: Infinity War on its 5-year anniversary. After the titular superhero team last assembled back in 2015's Avengers: Age of Ultron, Avengers: Infinity Wars gets the gang back together again, albeit under very different circumstances. Facing off against Thanos (Josh Brolin), who is determined to use the Infinity Stones to wipe out half of all life in the galaxy, the Avengers reconvene for a massive battle in Wakanda. The Russo Brothers' 2018 film was a hit with audiences and critics alike and ended on a major cliffhanger that set the stage for Phase 3's epic climax, Avengers: Endgame.

After Twitter account Marvel Perfect Gifs & Clips (@MCUPerfectGifs) shared Avengers: Infinity Wars' trailer to celebrate its 5-year anniversary, fans began responding to and quote-tweeting the post, expressing deep feelings of nostalgia. While some remember the intense excitement they felt upon seeing the new look for Chris Evans' Captain America, others recall the trailer giving them "chills". Some even claim that Avengers: Infinity War represents the best era of the MCU. Check out some fan tweets below:

Why Infinity War Is One Of The Most Beloved MCU Movies

Over the past 15 years, there have been a number of memorable and ground-breaking MCU movies, including Iron Man, Avengers, Captain America: The Winter Soldier, and Black Panther, but Avengers: Infinity War still clearly holds a very special place in many fans' hearts. In 2018, it had been 3 years since the last Avengers, meaning fans were excited to see the team get back together, especially since it would include new heroes like Tom Holland's Spider-Man and the Guardians of the Galaxy. What's more, Thanos, the film's big villain, was first teased back in the post-credits scene for 2012's Avengers, meaning fan excitement regarding his arrival had slowly been building for years.

One of the biggest criticisms levied at Phase 4 of the MCU has been that it feels somewhat directionless. Avengers: Infinity War, by contrast, was the first part of a years-long culmination of stories, with each movie leading up to its release serving as an additional puzzle piece being put into place. In addition to featuring some of the best action sequences and character dynamics in the MCU, the film's ending was also a franchise first. After the Avengers assemble to take down Thanos, Avengers: Infinity War ends with Brolin's villain winning and wiping out half of all life in the universe, including a good portion of fan-favorite heroes. Although most fans knew these heroes would be returning somehow after The Snap, the downbeat cliffhanger ending featured a handful of genuinely emotional moments, including Spider-Man turning to dust in Iron Man's arms.

Now, even years later, Avengers: Infinity War clearly represents a high point for the MCU for many fans. Avengers: Endgame is also still well-loved, but Avengers: Infinity War marks the first time the MCU had really attempted a movie of that scale, and they largely knocked it out of the park. With the arrival of Jonathan Majors' Kang the Conqueror and the promise that Avengers: The Kang Dynasty and Avengers: Secret Wars will wrap up Phase 6 of the MCU, perhaps Marvel will be able to reclaim some of that same Avengers: Infinity War hype in the coming years.