After 21 films, the first decade of the Marvel Cinematic Universe is coming to an end with the release of “Avengers: Endgame.” The long-awaited film arrives in theaters tonight, with impressively high box-office expectations.  

         “Avengers: Endgame” has already broken the record for the most first-day ticket sales in movie history, breaking the record in only six hours. “Endgame” also doubled all the first week sales for the previous film, “Avengers: Infinity War.” Ticket sales were so extreme that some sites, such as Fandango, were shut down.

         The high anticipation for the end of the “Avengers” series partly stems from a variety of teaser trailers, posters giving away the surprising return of past characters and a long stream of potential theories. The main reason behind the intense eagerness from Marvel fans, however, is the ending of “Avengers: Infinity War,” which concluded with Thanos wiping out half of all life. This ending, now known as “The Snap,” includes the demise of dozens of beloved characters accumulated by the Marvel Universe. With such a shocking ending, Marvel fans turned to wild speculation about what could happen next in “Avengers: Endgame.”  

         The first of the trailers was released in December, giving fans more questions than answers as Tony Stark was shown drifting in space, claiming to be out of food and water and almost out of oxygen. It appears as though Tony is on the Milano, the Guardians’ ship, which made an appearance in “Infinity War.” The hero is seen recording a heartbreaking message on the remains of his Iron Man helmet, which is likely on its last leg.

         Arguably, the most mysterious part of the first trailer is the reappearance of Scott Lang, also known as Ant-Man. Marvel fans assumed Lang was still stuck in the Quantum Realm after being sent there in the end-credit scene of “Ant-Man and The Wasp.” The “Endgame” trailer, however, ends with Lang at the Avengers compound, asking to be buzzed in. A popular theory for this situation states that Lang escaped the Quantum Realm by using the portable Quantum tunnel located inside of Hank Pym’s van, seen parked behind Lang in the “Endgame” trailer.

         Another full-length trailer for “Avengers: Endgame” was released to unsuspecting fans early on March 14. This trailer, unlike the first one, gives audiences a better understanding of the events going on in the film. The clip gave viewers a look at the first interaction between Thor and Carol Danvers, better known as Captain Marvel, a powerful and headstrong superhero. Including the moment in the trailer was crucial due to the worldwide success of Marvel’s latest film “Captain Marvel,” staring Brie Larson. The second trailer also contained flashback sequences from past films, unique superhero team-ups and a look at the new outfits for the characters.

         Directors Anthony and Joseph Russo, better known as the Russo brothers, have provided plenty of “Endgame” footage through “special-looks,” trailers, film-clips and even a Super Bowl commercial. Although, it is difficult to pick out every hidden spoiler or deep meaning, the trailers have at least revealed enough for fans to understand the overarching plot for the film. “Avengers: Endgame” will focus heavily on the fight against Thanos and saving Marvel’s fallen superheroes.

         “Avengers: Endgame” is rated PG-13 and releases in theaters tonight. Tickets are available through various movie websites, as well as in theaters.