The film ends with the Avengers defeating Loki and his Chitauri army, with a celebratory gathering at Stark Tower.
However, there is a post-credits scene that serves as a tease for future Marvel Cinematic Universe films.
Here's what happens:
* Scene 1: Nick Fury (Samuel L. Jackson) arrives at a diner where the Avengers are enjoying a meal. He tells them that they're not the only ones out there, showing them a picture of Thanos, who was mentioned briefly in the film. This scene sets up the events of future films like *Guardians of the Galaxy* and *Avengers: Infinity War*.
* Scene 2: This second post-credits scene is a humorous gag, where we see a group of scientists in a lab trying to figure out what happened to the Chitauri army's spaceship. Thor is eating his burger and says "That's my friend, Thor!" in a booming voice, reminding the audience that the God of Thunder is still alive.
While not a "secret ending" in the traditional sense, these post-credit scenes are very important to the overall narrative of the Marvel Cinematic Universe and are definitely worth watching!